Why is Metamask not compatible with non-Ethereum blockchain objects?

Was just thinking, how is it that exchange wallets (like a Binance or Gemini account) and other wallets like Trust or Exodus are compatible with various cryptos, but Metamask is not? Is there a technical term for this difference?

Edit: I understand that Metamask is an 'Ethereum explorer' so it would only NEED to be compatible with Ethereum blockchain, but I'm wondering what technology it is exactly that enables other wallets to be multi-blockchain-compatible.

Edit 2: Or am I visualising it all wrong (I came across the statement that wallets don't actually HODL any crypto -- they technically are just keys) and actually a wallet just acts a key that various different blockchains can accept?

Edit 3: It seems like e.g. Trust is actually an account that compiles a bunch of different wallet addresses and keys for different blockchains, so it's actually an aggregated wallet, not a single address that's compatible with a bunch of blockchains... So maybe i've answered my own question. Would still love to have someone who's more familiar with this weigh in though.