I don't understand either why Binance, Coinbase, Crypto.com, Trezor, Ledger, BitPay, Bitrefill and similar companies don't advertise. Logically, they should be here but they aren't.
Asking the question is answering it: you already know them. Most advertising here comes from new sites who want new users.
You are maybe right, but some casinos are way more famous than Crypto.com, Trezor, Bitpay or Bitrefill and they still have ongoing signature campaigns here. In addition it doesn't explain why less known exchanges or other non-gambling platforms don't advertise here anymore. IMO this forum is less reputed than it used to be because despite the merit system, some sections are still too much spammed for being interesting to read, or even to stay readable unfortunately.