The big companies probably want more control over the project than LibreSSL will allow them. They've been burned once by relying on old-style Unix community dev. But it's also entirely their own fault for not funding and auditing the open source code they were building their billions on.
Seems to me LibreSSL is the way to go, but I can also see why the corporations would just use it as a side-stream for hints on what to fix. They have enough resources to rewrite openSSL from the inside rather than the the LibreSSL tear-down approach. Having both projects is really a benefit for LibreSSL as longs as it gets sufficient interest and resources.