I'm not sure if it is all doom and gloom for open source. Development in the IT industry - particularly as it relates to graphics (as far as I can see), is exploding and I believe that there are many more developers than there are jobs available at flag-ship companies like Adobe. In a market like this, people who want to showcase their development talents presumably write stuff for open source products (no entry fee required) and then sell their mods on the net for what they think they may be worth or give them away free. With the huge numbers of IT professionals now coming into the market from places like India, who knows? We might even see comparable competing products to Photoshop, although PS will always have that huge, huge advantage of people not wanting to learn new software. Ah well, that's the dream anyway.
Sadly for me, I started life using Paintshop Pro (the cheaper alternative) and wish I'd just started with PS. Virtually every book and magazine on graphic art is written for PS. It just frustrates me going through a PS tutorial and having to 'translate' it for PSP. I'm really going to have to get my finger out and start using PS so I get used to it, but the thought of having to relearn basic commands which I know automatically for PSP just fills me with dread.