Wall warts are popular with manufacturers because it simplifies product design and approval. But WW are not very popular with customers.
Last century at my old day job , I designed a mega wall wart replacement, essentially a rack mount transformer with multiple isolated output windings that could replace something like 8 wall warts. This was not cheap and not embraced by the larger part of the market.
The customer is always right, and Peavey lost their love affair with wall warts last century, while I suspect they will never completely go away.
JR