98 people out of every 100 could run Linux as their main operating system tomorrow, and the 99th person could run it in 6 months when (X app) they are waiting on is finished/upgraded etc.
However, people have varying levels of excuses they use not to do so.
There is also a very nice Photoshop clone that has been ported to Linux. It's nonfree, but A LOT cheaper than PS... check it out at http://pixel32.box.sk -- TomHibbert
The reason that the answer to all these questions is 'true' is that you are asking "Why can't I have Windows Feature (x)." LinuxIsNotWindows. You just need to change your mindset a little.
One page links to ExcusesNotToRunLinux: