Interesting opinion, Farmer. I hope not everyone shares it and will be willing to share their secrets for managing their new printer longterm. Here's why I think that is a reasonable hope (despite what I take, perhaps mistakenly, to be the tone of your reply):
1. Your pricing for these printers is a trifle exaggerated. Vistek is currently selling these machines for $3599 CDN (P7000) and $5649 CDN (P9000). This is low-to-mid four figures, not "five" as you state. It is comparable to the prices I paid for my Nikon D810 and D2Xs. I have always semi-regularly cleaned my own camera sensors despite the fact that Nikon does not intend me to do this and cleaning this way takes a camera out of warranty. I further believe that I am not alone in doing this. Changing the wiper blade is comparable to cleaning a camera sensor, perhaps even easier and certainly less risky.
2. I believe many people have changed their own wiper blades with the 7900. There was (is) a famous thread on this very website in which many people discussed doing their own maintenance; one of the extraordinarily helpful people in this thread, Eric, even created a video showing how to change the wiper blade. And the point is, changing the wiper blade is not like doing head replacement surgery; it is a fast, easy, and low risk maintenance task.
3. Having Epson change a wiper blade for me is going to cost several hundred dollars and perhaps more importantly take my printer offline for at least several days. This for a five minute, low risk task using a $25 part if I do it. I would prefer not to incur these costs in time and money. Again this is like my decision to do my own sensor cleaning with my camera; I could send it away to Nikon for them to do it, but at a cost. As someone who depends on my printer to work properly every day, having to shut down the printer and wait an uncertain amount of time for Epson to come out is something I would prefer to avoid.
4. The widebed print people whose operational methodologies I have observed in the past always did their own basic maintenance; not necessarily the complicated or risky stuff, but always the simple, low risk, high impact stuff. Admittedly I have not known a lot of such "professionals" but I respected them for keeping a high quality operation going. Again this is like many dedicated camera owners who do their own sensor cleaning rather than send it away and wait idly while someone else to does it.
Please note that I am not saying you are wrong to prefer to have Epson change your wiper blade and other basic maintenance tasks. I am only saying that it is perfectly reasonable to have a different opinion. I will also be surprised if your opinion represents the majority in this forum, given the previous willingness of many 7900 owners to do such things, as I have described above.
No intended tone, just a factual statement. You're looking for information, so I was looking to present some and to let you draw your own conclusions based on the sum of all the information you collect. That's still my intent, not tone :-)
Most people who post here aren't even vaguely close to most people who use the machines. It's ever the case on the net, and the majority of people who bother to post are those who have had issues, so the sample group is generally poor as a representation of the wider user base.
1. We're not all North American, and most people invest in a system, rather than just a single printer, and I was a little broad in my comment as I was thinking of the wider range of products across various ink technologies as well, which did take us off the path a bit. Even at mid to high 4 figures with a total system investment, doing something (particularly during the warranty period) which you are not trained to do, do not have the specific tools and utilities to do, is not something for everyone. The new machines, too, have new heads, so a direct comparison to the *900 series may not be applicable. You've already noted that you can't just move the head out in the same way. I simply suggest caution and consider the real value to the business of a few hundred dollars to have a tech preventatively maintain your unit, compared to the risk of doing it yourself. You might be a very well trained technician, but most people aren't. Also, if it's done preventatively, there's little reason your machine should be down for more than an hour or so.
2. Many people have, but most don't. The choice is yours. Some people do their own plumbing or service their own cars. Most businesses, though, engage other professionals to do that work and instead focus on their core competencies to generate revenue. If a professional that you engage gets it wrong, you have recourse to them and not so much if you get it wrong. If you're a hobbyist, of course that might change the balance.
3. I think there's a misconception when you compare a wiper blade with a sensor cleaning. There are levels of sensor cleaning. The automated, the manually invoked but camera performed, and then physically doing it yourself. The functionality is in the camera to gain access to do it and it's designed for it to be done. In the case of the wiper blade, you're talking about replacing part of the cleaning mechanism, and you're missing the complete package, as it were. That might be enough, which is great. Again, the cost, I've already discussed that so I won't labour the point nor about the downtime. I will say I understand your need to have it working every day, which to me says it's a critical piece of capital in your business and that's why I find it difficult to understand why you wouldn't make a small outlay to have a professional keep it at its peak, but if you've done your sums then only you can make that decision.
4. Yes and no. Do you mean solvent and dye sub? Sure. Dye sub mostly because they were bastardising machines to run the inks so they couldn't get manufacturer support and solvent because that was more akin to the big metal type press guys in the sense of who and how they were operating the machines. When you move over to graphics, photo, proofing, CAD and that sort of thing, very few do their own maintenance. Solvent is also changing as the units become more mainstream and wider in application, and even dye sub in some instances as more manufacturing support appears.
So, yeah, more opinion above but in response to your thoughts and points. It's just information for you to use to make your final decision, but again, the reason you're not seeing a lot of people comment here about these units I believe is because most of them are not doing this themselves.
However you go, I hope it works out and you get great use out of your machine :-)