I've read other people make this point. There are a lot of TLS implementations out there but OpenSSL was so synonymous with SSL/TLS for so long that it became a fundamental building block. If an API could be established that lets the-thing-that-does-TLS become a minor detail that's easily configured we'd all be better off.

Removing the dependency on OpenSSL is going to be a challenging, messy job. OpenBSD has mostly transitioned over to their LibTLS API but even they had difficulty moving some projects over.