You say this like it's a bad thing. IMO, chess is a perfect exemplar of what I like in a game -- easy to learn, hard to master. Evidence that people like games like this? Chess has been around for >500 years.
I wasn't joking when I suggested it. Chess is the best game I know of that fits the "easy to know, hard to KNOW" criteria. But chess is hardly a 'mech sim
I can't get some of those older titles to work on modern Windows, so I use a virtual machine running Windows 98 to play them, now. It works out pretty well for games that don't require hardware accelerated graphics. Some of the older stuff runs well on Linux using wine, too, like Deus Ex.