... and a lot of times I go right to the brand to buy "straight" from them and they fulfill orders from Amazon so why not just buy from AMZN where I already have an account, get lots of credit card points, can spend my credit card points, etc.

In the last year I've seen this other kind of consolidation where most of the brands that don't have an AMZN-hosted or fulfilled store are using shop.app (now shop.com!) from Shopify. I did a stint of investigating boutique perfumes [1] and it seems almost everyone in that business uses Shopify.

[1] you gotta try "Under the Lemon Trees"!