[2023] Jet engines nerfed to the ground. On purpose?

The fact that jets have used tungsten for some time has made them a bit lackluster since before AAT.

You can always build a synthetic rubber industry, but there is no such thing as a synthetic tungsten industry. For a long time, I've considered them a bragging rights upgrade more than a practical one in most situations. You've probably long since wiped out opposing air forces (or had yours wiped out) to a point where introducing a marginally better plane wouldn't matter.