1. Then where have all the lumbering giants gone? The only player anything like Eaton in today's NBA is Roy Hibbert, but he's still a much better athlete than Eaton ever was.
2. A well executed pick and roll, sure, but what I was trying to get at is that today's guards and wings are able to consistently create better separation from their defenders. Bigs are required to help AND recover a lot more quickly now than they were in the 1980s. That today's guards and wings are a lot stronger and quicker doesn't help.
I get the argument that you're making and it's quite reasonable to presume that the way the game has changed would hamper some of the strengths that made Eaton effective. The problem I'm having is this:
You're saying that a guy who is one of the best defensive big men of all time, a former all star, a 2x defensive player of the year in an era where people actually played it, the all-time leader in blocks per game, and a guy who Hakeem Olajuwon said was the toughest matchup he ever had to go against, would be a scrub in today's game? When? His rookie year? Mid career? Nearing retirement? I suppose if you've got a team coached by a D'Antoni or Don Nelson, or had a roster assembled by David Kahn, then maybe this would be a reasonable position. But we're talking about a scrub. The chronological elitism is ludicrous.
Though there's been a movement of big guys being able to shoot more from the outside (more fours than fives) the vast majority (especially considering guys off the bench) are not producing in such a manner to render an Eaton useless. Rule changes allowing for a zone would increase his value for any team wishing to have a legit anchor off the bench to run a zone. The proliferation of guys who are athletic slashers without any outside game would further highlight his lane-clogging presence. In today's game he'd get paid. And he'd play. He wouldn't be getting 30+ minutes like he did on his prime, but he'd be seeing the floor and contributing in meaningful ways. Yeah, there aren't many lumbering stiffs in today's game. But it's not like those lumbering stiffs out of a job now would have magically been solid guys on an 80s/90s squad.
Pavel Podkolzine couldn't make it in today's NBA. It's not because he's a modern-day Mark Eaton. 25 years ago he wouldn't have been Mark Eaton. Today's stiffs aren't Mark Eaton.