D6 are also common today because they help simplify the user experience. Charts, tables, and fancy dice get in the way of learning the rules and having fun for the average person. Most people need to perceive a low barrier to entry and don't want to invest in learning a large ruleset.
Games you mention are still made, but they're a niche product in a niche market.
Needle moving growth for the tabletop industry comes from introducing new people to the hobby, not from selling another Space Marine model to an existing gamer. It's difficult to build a sustainable tabletop business without one or two big hits (ex: Days of Wonder's "Ticket to Ride"). It's even harder for companies that sacrifice usability for realistic simulations.
Games you mention are still made, but they're a niche product in a niche market.
Needle moving growth for the tabletop industry comes from introducing new people to the hobby, not from selling another Space Marine model to an existing gamer. It's difficult to build a sustainable tabletop business without one or two big hits (ex: Days of Wonder's "Ticket to Ride"). It's even harder for companies that sacrifice usability for realistic simulations.