With the huge decline of unions there's no way the old ways are set in stone. A freshly unionized field should take care to make sure new members don't loose the politics and enthusiasm, leading to decline a generation later.

Unions lost for a couple of reasons: their feet were cut out from under them via outsourcing/globalization. They didn’t/couldn’t picket moving factories overseas and both political parties were complicit in this.

Similarly the economy moved toward services and unions didn’t prepare for that.

Three unions ossified, became political and self-serving (not looking after their workers solely but looking after the org for its own sake and its bosses.)

Yes this is all true to some degree. Check out the first article of https://libcom.org/files/Rad%20America%20V10%20I5.pdf for discussion of the changes to union structure at their peak which may helped along the 3rd.

My original point is the old unions have no leverage not to acknowledge this and accommodate the concerns of a newly union members in a freshly industry.