Earlier quoted context omitted.
There were free options. I think the biggest benefits to Let's Encrypt are the EFF's clout and the simplicity.
No there were not. Free options meant untrusted certificates or short-lived certificates that could not be renewed. LE made SSL free, trusted and long-term. You could have made it twice as hard to do the initial setup and people would have jumped at the opportunity regardless.
The former doesn't allow commercial usage, while the latter operates in China. That's probably why it wasn't an option for a lot of people. (That, and the terrible UX at least in StartSSL's case.)