most players here have had coaches/ high school chess/ college chess. etc.
Not even remotely correct. Most players here are very casual and many join without fully understanding the rules.
If Chess.com were to have every single position of every game evaluated by Houdini that would be a tremendous waste of computing power and probably not very helpful. You need to understand your game yourself, just knowing wether or not Houdini would put a "+" next to your move isn't going to help you if you don't understand it.
Because there's a difference between checkmates and resignation? lol
Haha, way to prove JMB's point.
The difference is that beginner level players end games in checkmate because they and their opponents are too inexperienced to get any benefit from or understand resignation.
JMB sums up blitz games well. Blitz is about finding adequate moves quickly. If you take the time to find good or best moves too often, your rating will be lower than it could be. And blitz evaluations are different anyway. If your "blunders" create lots of complications for your opponent, then your position is probably close to winning.
If you want the game to be more about skill, then increase the time control. I'd suggest 10-15 second increment too.