I don't tend to game on the PC like I used to, so I don't have an answer for any of your games. So, yes... windows is probably a stronger arcade... though I've been more impressed with what Flight Gear can do than I ever was with the Microsoft Flight Simulator. Like many, I've moved my gaming to the Wii, or other consoles.
Hulu and other services provide instant viewing on Linux just fine. The Roku device which allows Netflix instant viewing is Linux-based, but for some reason they continue to deny access to Linux on their web site. This is a decision they have made... not a technological barrier.
I probably don't do the same things with graphics that you do, but I've found GIMP perfectly usable for anything I hand it. I've touched up photos, including removing reflections and other matter from photos, touched up blemishes and red-eye, and a number of other things. I've also used tutorials written for PhotoShop to learn how to do things in GIMP when they were about artistic technique and not idiosyncrasies of the tool. If you want Adobe PhotoShop, precisely and exactly, then it will need to be done by Adobe. That has to be their decision.
There are options to do things like Adobe Flash, including the OpenLaszlo project. Again, they are not precise and exact clones of Adobe. That's the funny thing about intellectual property is that when you create an alternative technology it has to have some differences from the existing version or you end up in court. Again, Adobe has made a decision on this... and if you're letting Adobe determine your technologies then you'll have to follow their lead and move when they say you can.
I've used TurboTax online for the last several years through Linux with no problem. I think their official decision is that they want to move people online and that version works for Linux. It's not free, but I'm not concerned about free... only that it will work for my environment. If everything must be free then I guess anyone can be right in this argument by only choosing technologies which have cost associate with them.
I don't know much about Stone Edge, so I can't say much about it. Looking at the web site it seems to be a pretty specific tool. A lot of people build their computing (and even their business) around a particular tool. If the tool doesn't do it, they don't either. If the tool must do it, then it becomes a core part of their methodology. If you've built your work habits immutably around how specific tools work, then you have to follow the tool.
It is probable that you will never be in a position to move to Linux. That's OK. You need to stay in your comfort zone and where you feel you are most productive. (I know one guy who still swears by his index cards... and they still sell them at the office store.) I think, though, that there are many users who don't have your specific requirements who would find that Linux does everything they need to do "out of the box." I think many who are new to computing would easily develop the knowledge and flexibility on a Linux system in the way that you have developed it on Windows. Many who get the chance to try Linux will make the choice to stick with it... not all... maybe not even most. Isn't what's on each person's computer really about what works for them?