The real plot problem is that not enough effort goes into game plot development.
I dunno - sometimes they over-do it, taking themselves way the hell too seriously.
I think the coolest game I ever played is still an old-assed text-based game. The game came with a scratch-n-sniff card, a 3D comic book (with glasses), and just enough 'plot' to get you started. The plot is is scare quotes because, quite frankly, it's intentionally stupid, silly, risque - but hellishly funny. The game itself required a ton of imagination on your part (because it was all text-based), and a lot of mental recall to avoid getting lost, killed, etc.
Even now, 2+ decades later, I still get a smile when I think of the so-called "plot" (it begins in Upper Sandusky, Ohio, then instantly puts you on Mars, etc...)
That aside, here's something else to consider: one of the absolute most popular games of the '90s was the Doom/Quake franchise, right? The 'plot' for Doom and Quakes I, II and III were thin at best, and let's be honest - it only got in the way of the real reason we all played Quake: Kill shit in realtime 3D and watch the gibs fly. The big 'plot' in the CTF/Team Foretress/WeaponsFactory MODs, and in CounterStrike and suchlike? Really - what plot?
I guess what I'm getting at is this: a plot is only useful sometimes - not all games need one, and if a game really needs a heavy, complex plot, then maybe it's just trying to cover for crappy gameplay?
To add to your point:
Pac-Man, Donkey Kong, Pong, Tetris: What story ? There is hardly one there, if any. Eat pellets, get high score. That is Pac-Man's story. Tetrris? None. Donkey Kong? A big ape stole your girl. Get her back. The end. Pong? Use paddle. Don't miss the ball.
The point is: Story is not that important in video gaming. The level of immersion and interaction and how a gamer does this is key in the suspension of disbelief in a game. A lot of times, gamers can't even remember the story, just that they did something in the game.