Export: OK, so now some odd fanboyism comes into it. More like anti-Steam than pro-GOG, I admit. Not only are you making the comical assumption that a major company like Valve are "stealing" DOS emulators, you're also back-peddling on your earlier claim that Steam has compatibility issues and instead switching to some vague implication of unfairness.
Steam works just the same way that GOG does, legally speaking. Neither GOG or Steam games open up with a big splash screen saying "Thanks DOSbox" or "Thanks ScummVM". But of course, both companies have deals with the third party companies that make it possible. The only difference is that GOG has no DRM at all whereas Steam has relatively light DRM (i.e. it doesn't care how many computers you install it on and even has the "Steam Cloud" thing that shares your save games over all PCs you install it to, if you want it to).
Steam has to have some DRM or the modern publishers wouldn't let their current games be sold on the service - it's a lot easier to convince someone to do a DRM-free Gabriel Knight than it is to do a DRM-free Assassin's Creed Brotherhood. When a certain company did insist on putting their own DRM into a Steam release of one of their major games, bound to either be EA or Ubisoft, Valve removed the game from Steam themselves and Gabe Newell issued a statement that Steam isn't going to stand for that on their service - so GOG and Steam are more similar than fanboys would like to think.
I'm not assuming, I've talked to the DOSBox creator personally, and he's not happy about it. I wasn't back peddling, I was being more precise with my complaint. To back peddle would be to say Steam doesn't have compatibility issues. Some games do -- that much was consistent. I'm not anti-Steam, I'm just saying there's no sense in buying old games from Steam (excepting those that use emulators) when they're updated for compatibility here. As with GOG, Steam does a lot of good things, but they certainly have flaws. Not interested in semantics.
I realize they're not required to do so, I just think it's the kind, human thing to do. If we all only do what we should all the time because it's legally required, well...goodbye humanity. They owe some success to DOSBox -- they should at least get approval from its creators.