Sure there's occasionally issues with source media or how it was imported, but the big difference: I can fix problems with emby/plex. I can correct messed up metadata, or run a partially corrupted file through a converter to fix it, or just replace files entirely; all in a few minutes. (and none of these I have to do very often. Like one or two files a month, while constantly adding new content daily)

Most of the problems paid streaming services have, just have to be delt with until the provider gets around to fixing it, if they ever do at all. Then you add on content being scattered across 10 different services, artificial quality limitations, tracking, lack of or very poorly implemented offline playback, the inability to share with friends/family, advertising (now even being added to services built-on being 'ad-free'), the list goes on...

As a note: I use Emby and have never had an issue losing my watched position and have only had maybe 1 in 1000 items incorrectly identified (out of a library of 4k movies and 34k tv epps).