Ben, a fair amount of what you are saying above is incorrect from my experience.
Whether or not inkjet printing is expensive compared with a lab depends on what size you are printing, how much customization you need, which inkjet printing system you are using and what kind of paper you need. One cannot generalize about this. Maybe you have one specific set of needs that come cheaper from your labs, but that is not the universe of situations.
Calibrating the printer takes about 2 minutes to print a target, and if you do your own profiling about 10 minutes to create the profile. If you send the target to a professional profiling service, the time it takes to mail the target, and about 50 dollars more or less. If you have a friend with a profiling kit, the friend can make it for you free - if a good friend! If you plan to use alot of different papers it may pay to buy a profiling system for about 1000 dollars, otherwise, you get a few profiles made and use them repeatedly. If you buy a RIP say from Colorbyte the profiles are included and any other profile you need is made free on request. ImagePrint RIP does all your layouts and is programmed to minimize wastage of paper relative to the layout parameters you give it. Many professionals swear by it for this purpose.
You can read my articles on this website about the cost of using an Epson 4800. But Epson is not the only show in town any longer and I understand other makes are less prone to clogging. The Epson 4800 is a substantial improvement over the Epson 4000 in this respect.
Inkjet printers - especially Epson's professional machines are built like tanks and physically they will far outlive their economic life, which is determined by technological obsolescence, not by wearing-out. You can keep it as long as you are happy not up-grading to newer technologies. That is a matter of personal choice.
Inkjet inks for whatever prevalent model you buy will most likely be available for years after most of these machines have been re-cycled out of use. We can't make iron-clad forward-looking statements about long-term availability of ink cartridges, but I've seen ZERO complaints anywhere on the internet about people not being able to get the supplies they need for their printers.
The general professional consensus is that this technology is mature and the highest quality black and white printing is now possible from the latest model inkjet printers being produced certainly by Epson and most likely by the new Canon offerings. You will find material on this website and in the L-L Video Journal attesting to this. There will always be people who refuse to believe this, but that is their problem, not an objective reality.
I have been doing inkjet printing for the past six years, starting with the Epson 2000P, graduating to the 4000 and since last November a 4800. I am doing work I never thought possible in both colour and B&W and there is no way I would even dream of getting into a wet-lab environment again, whether for colour or B&W - it is for most intents and purposes so surpassed that it's not worth talking about.
Considering what you get and the flexibility and possibilities it offers, and by the time you amortize the initial investments over a reasonable volume of output, this is a bargain and it will most likely keep becoming cheaper in real terms.