Yep, you're right, I agree, to a point though.
There's a quote from an Indian restaurant owner in the 70s or 80s that said we've got away with selling onion gravy with a few bits of chicken in it, Indian curries were better then. I leads me to believe that the stock for a really good curry is not going to count to the final taste.
The boiled onion base must've the one they all used back then? No carrots, no peppers.
Which leads me to conclude that the base gravy has no reflection on the curry you produce. It's the way you cook the ingredients, mostly the cheapest you can find, altered, that gives the final taste, not the base.