Adobe can get away with questionable business behavior solely due to a lack of alternative products of equal quality.
What questionable business behavior?
While Adobe DID push Suite upgrades, they offered what was seen as a "deal' by the buyers of the Suite. Those people who took that route perhaps didn't pay too close attention to what the deal meant to their point purchase license...but those customers got exactly what they wanted, an upgrade to a Creative Suite which included a ton of software for a price much less than buying them outright.
Not sure what was questionable about that other than the fact they didn't promote the heck out of the fact an upgrade of any point product to the suite meant they now owned a Suite license not a point product license...
In point of fact Adobe bends over backwards to try to do the right thing whenever possible...you may not "like" some policies but it's not like they are trying to actually screw their customers...
Oh, and trying to find an alternative to Photoshop? You are kidding, right? Coral Photo Paint and GIMP come to mind...yeah, right, not really an alternative :~)