Well sure, OpenSSH is probably one of the most useful and versatile tools out there, there's no denying that it's a huge achievement.

That being said it's a program with mostly well defined use cases while OpenSSL is a library used in thousands of programs (including OpenSSH) on a variety of hardware and operating systems. The OpenBSD project naturally mostly cares about OpenBSD first and the rest second, which might be a bad thing if we end up with a multitude of forks each supporting a particular OS/architecture, increasing the chances of messing things up. After all, the latest big OpenSSH vulnerability was due to debian-specific patches...

Also, for what it's worth, sloccount tells me the latest snapshot of OpenSSH has about 90 thousand lines of code while OpenSSL has more than 360 thousand. It's a huge, huge library, forking and maintaining it is a tremendous undertaking, even compared to OpenSSH.