Seems to me that any team that goes perfect or near perfect in ST automatically has a really bad year. What gives???

Why don't teams carry momentum into the new season from ST?

because ST is worthless and teams usually play their minor leaguers the entire time.

Brooklyn, in Jersey you are playing your regulars and leaving them in all game. Meanwhile, most other teams are giving their regulars only enough playing time to keep the rust off and are giving lots of time to prospects. Your ML hitters better do well against AA pitchers! Its fine to do it your way, but are missing out on some extra prospect development and also your regulars will tire more quickly in the regular season.

Of course, you are also winning in ST because you spent $122M on salary and put together a very good team.

The ABs carry over to the regular season, so you really don't want to give your MLers too much ST playing time. I try to max out at about 20 ABs and 8-10 IPs. The rest of the PT goes to MiLers.