I believe the issue is more complicated. 70's-90's playline might not had the best articulation or even *sculpt (Kenner SW figures were completely outdated when they were released both in articulation and sculpt), but they were much more fun and creative and I wouldn't call them cheap as they were limited by technology of that time. The vast majority of the few advanced action figures are heavily pandered to adult collectors (TF generations, ML, GI Joe, WWF, etc.) whereas the toys that genuinely aimed at kids above preschool are indeed cheap tat; "shampoo bottles", hollow Cyberverse, Power Rangers with swivel hips, etc. The only outliers are Playmates, Panda Mony, Morphonauts they currently have KS
, Jazwares (Fortnite) and Spinmaster (DC).
Sadly, playline action figure aisle is dying thanks to mobiles/tablets, dull licenseshit and Hasbro and Mattel who bought out all the great toy companies from the past. There wouldn't be adult collector toys, if it weren't for playline. In general, action figures became stale; in contrast, I've seen fashion dolls, both playline and adult collector upping their games and coming with new joints engineering.
*In some cases, it's vice versa. For example, Mighty Max and original Polly Pocket which were hand sculpted
, still have better and more details than current attempts at miniature playsets. Even the old Micro Mutants by Playmates were superior to the new 2012 sets.