Gian-Reto, you are incorrect. The hobbyist game industry collapsed in the early 1990s and it ceased to exist. The more recent board games are what we call the "Neo-Hobbyist" game industry which is a completely different thing. Read my blog, it covers this quite extensively in an attempt to preserve this lost history and the epic stature of "The Big Three" and the vast influence they have on games even to this day, Everyone knows that D&D has been the most influential game of our time, few know that SFB and ASL are a VERY close second and third. All modern game design ultimately comes from The Big Three games... especially Star Fleet Battles. These games most definitely have been forgotten by the modern game industry, if they weren't then you would all be calling Stephen V Cole "the father of modern game design" but instead you've never even heard of him before. Which is a perfect example. You have heard the names, but know none of the story of what those games even are. ASL and SFB are not like any other games that have ever been made, they are on a completely different level. Both were designed by hundreds of people over a period of decades, no other games ever were. They are, far and away, in a class by themselves represent a level of detail and complexity with which modern gamers do not even have a frame of reference to begin to imagine. There is no question at all that The Big Three era was forgotten by modern game makers, almost from Day 1 in fact. They were absolutely certain that "board games are not relevant to what we do", I was there. I know.
Okay, let me try again...
1) At least one of your "Big Threes" is not dead, far from it. D&D is still played extensively by many fans all over the world. If you want to argue about the current edition no longer being the "true D&D expierience", be my guest. I am not really into D&D, I only have heard that there are quite some differences between the different revisions. I know from my expierience with Games Workshop games that such differences can make all the difference (3rd edition 40k was really taking a long time to grow on me... it never did until GW softened the blow with later revisions).
If that really warrants calling the game "being dead" I don't know....
2) Look, the fact your old Pen and Paper systems never got the fame they might as well have deserved (besides D&D to some extent) might be sad, but is understandable... they lost in popularity during the time when gaming wasn't mainstream yet, and just the initiated geeks knew that Dungeons and Dragons was NOT some Neo-Satanist cult.
There is no conspiracy behind these games fading back into obscurity, and no one didn't mention the guys involved with the creation of these games on purpose.
Just as with LotR, where people just use some of the "enhanced nordic mythology" elements that tolkien came up without even thinking about the source nowadays, because the tolkienized nordic mythology has become the accepted standart for high fantasy, so do people use gaming systems that might have been pioneered by D&D (though D&D certainly wasn't the first of its kind and borrowed heavely from earlier games) as accepted de facto standart for RPG games, pen and paper and videogames alike, nowadays.
They might not even be aware of the source. Because they are using mechanics passed down from the source indirectly.
3) Took the time to google your "neo-hobbiest games" phrase.... is that written by you -> http://www.gamasutra.com/blogs/MarcMichalik/20160602/271918/Tiny_Little_Branches_The_GameMaster_Series.php?
I got no other direct hits over google, so I guess this is a phrase you made up. Well, not trying to judge here, just make sure we are on the same page.
Now, working from the assumptions above I guess you are trying to express your own judgement of older vs. newer hobbyist games. I can relate to that, having seen the downfall of the once mighty, quirky, and pretty hard to get into GW games to streamlined, easy to pick up but depth lacking mainstream tabletop games.
But then, I have seen what a mess the older system was, how the additional depth was often just complicating things, and how games consumed whole DAYS because of the depth of the ruleset.
40k 2nd Edition was a raw diamond, but often unplayable if you didn't had to time to invest to both play the game (with single turns taking 2 hours and more to play out, and 6 turns to go), and read the many resources needed (resource books were HUGE at the time). I wasn't happy about the "Kiddification" of 40k 3rd edition, but to some degree without that, the game wouldn't have seen the success it did after that. It was just unplayable for most people in its 2nd edition state.
So, judging form what I read from you until now, you crave deep systems and a game that really challenges you to learn EVERYTHING about it, and has a ton of information to absorb. That is fine really, the crowd that loves such games is still around today. But as in the 70's and 80's, this crowd is really small. Most people cannot invest 12 hours into a Pen and Paper or Tabletop marathon, AND invest countless hours into reading all the resource books, creating their characters, preparing as game master, painting armies and whatnot.
Most people have a life beyond tabletop or pen and paper gaming. Newer games more and more cater to this audience, because it outnumbers the more dedicated group by far.