Much like creating modern gadgets isn't common knowledge today. Moggy didn't seem to know how to make Cuendillar, other than the basic theory (unless she was lying, but at that point, I think she was too scared of Egwene). Nor have we seen any of the Forsaken try to make any kind of ter'angreal or angreal. I think it required specialized channelers, complex weaves, links and laboratory/workshop facilities for the more complicated 'angreal.

As for Compulsion and Balefire, it's not surprising that those fell out of common usage, and even there, we don't know how common those weaves were during the AoL. Both sides stopped using Balefire, and were afraid to use it, so they were unlikely to keep teaching it, and Compulsion is heavily frowned-upon, not to mention extremely complex.

Travelling and Skimming are the hardest to understand or accept. But I've seen quite a few theories or explanations put forth. The land could have been in such a constant state of upheaval thanks to the Breaking of the World, that people avoided using Travelling to avoid attracting the attention of insane male Aes Sedai or remnants of the Shadow's armies. Or they were more focused on survival and less on finding and teaching new channelers. Or Ishy suppressed the knowledge. I don't know. I think even a combination of all these answers is still insufficient, but I'll accept it. Maybe Ishy worked very hard to get rid of the knowledge.


But even still, we've seen that some of the weaves were passed down. Moiraine probably learned or figured out the weaves for balefire after visiting Vandene and Adeleas in TGH and reading from their library. And Compulsion seems to be somewhat instinctual, at least in very primitive forms.