2. There is currently only one free cert provider, if there are ever issues with it, your users will see a scary error message which will make them think there are security issued with your website.
3. Downloading and running code from a 4th, or 5th party and giving it access to your config files is not "more secure".
4. The culture of fear around HTTPS, meaning only the "most secure" or "newest" protocols and cipher suites are to be used. This prevents older clients from working, where HTTP works just fine.
5. HTTPS is needlessly complex making it hard to implement. There have been several security vulnerabilities introduced simply by its use.
6. If you can't comply with the OpenSSL license, implementing it yourself is a hopeless endevour.
SSL was developed by corporations, for corporations. If you want some security feature to be applicable to the wider Internet, it needs to be community driven and community focused. Logging in to my server over SSH has far more security implications than accessing the website running on it over HTTPS. Yet, somehow, we managed to get SSH out there and accepted by the community without the need for Certificate Authorities.