1) Straight Talk can be honest with customers and admit there's a problem, instead of acting like we are all stupid.
After all, even you said "ST is very well knowledable about the fact there is an issue
but can't offer a fix in their systems."
2) Straight Talk and other MVNOs can put pressure on AT&T. Sure, that part may not work effectively, because AT&T doesn't want cheaper competition to work TOO well, now do they? Sort of like back in the '90s when Microsoft purposefully put bugs in their operating system to so competing office software would not run correctly... (Yeah, they did it and years later enough evidence was uncovered they paid a large settlement, but at that point it was too late for the competitor.)