The CEO of Square Enix was fired because he produced the latest iteration of Tomb Raider, and it arguably is the best iteration of Tomb Raider ever, and plainly didn't make any money.
Also your argument about 20 years ago is plain incorrect. 20 years ago DRM was way more strict and customer screwing than it is today. 20 years ago if you wanted to play a top of the line game, you would have to buy a Nintendo Entertainment system. Arguably the most restrictive walled garden system that has ever been in the market.
http://www.eurogamer.net/articles/2013-04-09-square-enix-tho...
http://www.escapistmagazine.com/news/view/123045-Tomb-Raider...
http://www.escapistmagazine.com/videos/view/jimquisition/712...
The North American release of the NES was 28 years ago now.
But hey, if you want to compare Doom on the PC when it came out in 1993 to Doom on the SNES when it came out three years later, and consider the sub-standard SNES port that's three years late to be a top of the line game, go ahead.
Although why Doom was used as an example (not by you, I'm aware), I'm not sure. I don't remember any copy protection on it.
There is also another important figure that is routinely ignored: the number of honest customers who get screwed by or annoyed with DRM and other forms of copyright protection (20 years ago we had to enter words from the game manual, page X line Y word Z, in the middle of the game) and decide to buy fewer games in the future (and possibly pirate them instead to avoid such annoyances).