I think it’s a mix of staleness and philo dough quality. The imported turkish stuff has to be made, packaged, transported etc , it gets cooled, whatever and takes ages to get to you. Meanwhile the dough is getting stale and absorbing too much of the syrup, so it becomes lower quality. Also, as you point out, it’s mass produced.

Also, the homemade greek stuff probably starts out with higher quality philo dough, and is made fresh that morning.

Not to say the greeks, armenians , syrians or whatevers don’t have the capacity to make better baklava, I’m sure they all have great chefs.