Putting my programming/hosting hat on for a minute here, it would be extremely challenging to do something like the church online platform as a stand alone plug in for a site. Even if the basics of just dropping in files were handled, you are not allowing for growth with load balanced multi-geographic diverse sites. You also would need stable content delivery networks that would be able to withstand things like denial of service attacks. You would then have the church online experience being represented by the widest range of hosting systems, from "we have $10 month to do this" to actual services that would be capable of doing the site. If the issues that are. happening now were split up across hundreds of individuals hosting it it wouldn't solve the problem.- it would just change the rate at which it happened. If your site went from 10 views a month to 10K views, you might hit the same problem and have zero resources to fix it.
TLDR; - They have found the issues because of greater weekly usage (Praise God!) and have found solutions to help alleviate downtime and issues.