Is IB Advisory Commoditized?

I'm finishing up my first year in the M&A group of an American BB.

After reflecting on the last ~10 months on the desk I've began to ask myself if IB advisory is commoditized.

Meaning, is there a substantial difference in the quality of advisory and deal outcome when you use a GS or Evercore relative to a Barclays or Guggenheim? I suspect not.

This job is not rocket science, and I'm sure that 95% of the analysts at Barclays/Gug are capable of the work quality that GS/Evr analysts put out (regardless of what people at top BB/EBs say, the talent across all reputable banks is pretty standardized and where you end up is largely luck/undergrad name).

If top MDs can leave, start their own shops, and instantly poach clients and see success (Frank Quattrone, Michael Klein, Ken Moelis) what does that tell you? To me, it says that business is driven by MD relationships and that most companies recognize that the product they get from GS vs CS or Evr vs Greenhill is the same (-> a commodity).

Obviously, there are times where you may need to use a certain bank ( i.e. M&A, capital issuances, and restructuring may call for 3 different banks), but does it matter in the end who a client uses, top or mid/low tier? I say no.

Curious to hear thoughts from bankers. Do you agree? If not, why? If you do agree, does this have implications on the long-term sustainability of IB, its huge paychecks, and massive advisory fees?