>successive administrations ignored the intent of the law, for so long that people began to rely on assurances that the law never promised. Now that the law is getting applied properly, those people are facing the consequences.

No, there's nothing proper about it and it has nothing to do with the merits of the visas in question. There is no law saying that the state department should make travel impractical for people USCIS has already decided can live/work in the US. The reverse is much more likely. They want to push people off of legally obtained visas by causing unreasonable delays.

H1B is temporary but you can have immigrant intent. It can be extended indefinitely with an approved green card application. Your employer is going to pursue that if you're on h1b and they want to keep you around. Many if not most h1b holders are in that category and will get a green card eventually. They are simply waiting for that to be available due to quotas based on their qualifications and birthplace.