Amazon isn't necessarily competing better (though they often are--even if im okay getting a slower delivery, not-Amazon vendor sites will do shit like require signature confirmation without the purchaser requesting it, which makes the package all but undeliverable to certain apartments), but they win on the guarantee that buying a product through Amazon isn't going to sign me up for an endless stream of marketing email.

Granted, Amazon has much less need for that endless stream of marketing email because they're already the de facto first choice shop. It's a lose-lose game if you're a conscious consumer and both want to support a non-Amazon monoculture for internet retail but also don't want to have to yet another drip feed of marketing email.

Ideally there'd be competition among email service providers to recognize the modern landscape of CAN-SPAM compliant but entirely unsolicited and unwanted email and provide user tools that aggressively bin non-transactional email and penalize senders that send 10 "transactional" emails for a single interaction ("here's your confirmation! here's a shipping update! here's another shipping update! are you satisfied with your purchase? leave a review!) as shadow marketing.

Either they're knowingly doing this for brand reinforcement reasons or are honestly clueless and don't recognize that a single email that links to a continuously-updated order status page is preferable. I figure mostly the former, but either way there are limited mechanisms to encourage vendors to make judicious use of email.