The issue with the TAI is ridiculous, but it has been identified and barring an easy fix (which doesn't look like it exists), the Feds aren't going to let it go. Boeing knows that and that's why they said they are just going to engineer a permanent fix and withdrew their application for an exemption. Every airplane has issues like this one. Most are fixed with some sort of service bulletin at their next heavy check or specified interval, but Boeing has used all of their hall passes and the Feds aren't going to go easy on them any more with this particular airframe.
We have, I think or at least hope, stretched the late stage capitalism, "let the free markets decide", anti-regulatory rubber band as far as it will go and are headed back in the right direction. As much as pilots detest the feds, corporations like Boeing and the airlines have made it clear that they cannot be trusted to do the right thing. Greed ultimately wins the day and you end up where we are now, with a 50 something year old airframe still being produced that was certified with almost zero regulatory oversight and by a company that consistently chooses short term profits over long term sustainable aircraft production and safety. I don't think history is going to treat this era kindly. Boeing has no domestic competitors left and is being propped up by the government. They have a legal monopoly and now we get to deal with the consequences. Decades of prioritizing profits over their products and people with loose oversight has resulted in exactly what we have now.