Earlier quoted context omitted.
Is it a practical issue where you are? In France I can't remember the last time I've had issues with undelivered text messages and I use them quite a lot (I generally use the cheapest plan I can find which usually doesn't contain data, so I default to texts). For important messages I'll expect an explicit confirmation anyway, it's not enough that the message reaches the recipient's phone, they also have to read it! M…
If you've had a long running group chat over MMS, ask to see everyone else's phones. Messages will be in a different order on every phone and there will be many missing messages. My wife and I do this regularly because we won't understand something said and we'll see one of us didn't get a message from the group.
-- a guy who used SMS and then had 90% of friends being reachable via IRC and email, and SMS for the rest - before entering the world of smartphones.