My thoughts are yes, red teaming has got significantly harder over the last few years. The knock on effect is:
1) engagements need more time,
2) teams who don't invest heavily in R&D (either in-house or outsourced) will be left behind,
3) there's less things shared publicly as a consequence,
4) lots of teams have tried to compensate by assuming breach, which as a result has led to less innovation in the IA space
However, I disagree that IA is anywhere near dead even targeting the top 1%. The vast majority of our engagements have a large IA component and we're still successful in >75% of cases. Yes the points mentioned are a pita - AWL is a great control, but there's equally a plethora of file formats that support scripting; get creative - Yes MOTW restricts some things - but there's a variety of ways around it if you're creative (and I'm not talking about ISOs 🙄)