Out of curiosity, do you buy software from small devs at all? It seems like, whatever the privacy/security implications may be when buying via Apple, they're worse when dealing with a totally unknown party.
Too many times I’ve tried to run App Store apps and been bothered with my Apple ID. I prefer the decentralization and not relying so much on Apple’s cloud services.
Trivial to pull up old license info from 1Password or email if necessary.
It's not a good user experience, and Apple's actions elsewhere with app stores are so utterly beyond the pale I cannot support that financially.
Plus there are other tools to further layer if it was ever a problem, like virtual credit card numbers. In practice the very nature of credit cards means it doesn't seem to generally be a problem, has been less of a real world risk than hacks of physical retailers. If I see a bad charge, I just report it and get a new number.
Also FWIW, I've seen plenty of sites starting to offer Apple Pay as an option at checkout, I assume it's getting built into more payment systems now. That itself is solid defense, at least as good as the MAS though sometimes the checkout flows seem a bit wonky still.
(Side note: to further deny us users our right of choice, ownership and control over our device, Apple has already crippled ALL application firewalls on its newest macOS to allow all Apple authorised software to BYPASS any such application firewalls, even if the user has explicitly blocked such software).