No, not videogames (though they are a factor). The big advance is the Web itself, and the critical mass point was the invention of the Wiki.
That's right, wikis are the killing blow.
Now, let me walk you through the reasoning as to why.
- The reliable buyers, for the longest time, were those who read more than played.
- This lead to the creeping influence of lore over practical tools.
- Wikis are superior IN ALL WAYS to publishing products for the distribution and proliferation of lore, making even "official" products obsolete and pointless wastes of time and money.
- With the massive money of lore nerds and related readers slipping away, only gameplay remains as a selling point.
- Publishers with atrophied game design skill and acumen (all of them that haven't moved to videogames) now realizes that it's got to play catch-up, and fast, or die out.
- Only those willing to embrace the Wiki, drop lore from publishing, and focus entirely on rules and tools will survive.
Not that game designers are in a great spot in tabletop gaming. Tabletop RPGs are, in practice, the farm league for the real money: videogames. That shit ain't going to stop anytime soon. (Neither will comics stop being the farm league for film and television; again, the real money is not in the farm leagues.)
Making a solid game isn't a viable business in itself, and the folks who started way back when are slowly realizing that this train is coming to the end of the line. (Some will crash into it because they won't admit that it's time to change; let them crash and burn.) It's a demonstration of your competency as a designer, while you ensure that you can also do coding competently when you get called up to the big leagues.
Assuming, of course, that it's not just a hobby for you. If so, enjoy a pastime that--if you're good--pays for itself.
But no, after 40+ years, the tabletop RPG medium is not a viable business any longer. It's never been bigger than Dungeons & Dragons (and there has never been a need for anything other than reskins of D&D, which the d20 System demonstrated quite handedly), so as its fortunes go so goes the entire medium world-wide. If you want to make RPGs, and you don't want it as just a hobby, learn to fucking code. Vidya or GTFO.
And if you want to tell stories, write proper fiction or GTFO. Gaming is for gamers, not frustrated writers, you lying shitweasels.