I get your point, but please do read the training logs for Meta's OPT, it's some Greek drama I tell ya
Which checks the box for great timing. All these companies with billions in the bank needing a new thing to prove they still warrant their growth valuation will dump obscene sums into this and cause things to evolve at a staggering pace, much like we've seen with AR and VR.
No, there is no real "hard part" to AI current. Training is simply "the expensive part".
It seems "the bitter lesson" has gone from reflection to paradigm[1] and with that as paradigm, the primary barrier to entering AI is cash for cpu cycles, other things matter but recipes is relatively simple and relatively available.
[1] http://www.incompleteideas.net/IncIdeas/BitterLesson.html