StartSSL is far from simple to use.
Anyone incapable of following the steps required there is probably not who you'd want implementing your web server security…
If you're going the minimally technical route then you're using shared or managed hosting and it's not your job to set up the SSL.
Crypto is non-trivial. There'll never be a proper "Click this button to automatically secure your random php app running in cPanel/Plesk".
The best we'll see I suspect is a "click here and make your website pass the minimal checks modern browsers use to determine if you're secure", then we'll have a daily stream of site owners claiming "the PII/password/creditcard breach wasn't my fault - I used 2048 bit encryption!"