I've been tinkering w rosters in SimMatchup in hopes to develop the ultimate team for a particular theme league... Apparently, this is totally worthless. The home team wins literally 85% of the games- usually in a blowout. I have a feeling this years' 76ers would consistently beat NBA Champions in SimMatchup if they were the home team... What is the point of even having SimMatchup on the website, if the home team has such an obvious, & obviously ridiculous advantage?

I haven't had that experience at all.  Maybe you can post some of the results here to see which teams you're talking about? My guess is you've just ended up with scenarios where the team you're making the home team is simply better.