Take just a single aspect of the gear - climbing rope, modern rope is a technological wonder, light, super strong and extremely dynamic, it's part of what makes it possible to push yourself to the limit and repeatedly fall off routes safely, with zero injury. After a certain point you cannot improve in climbing without pushing beyond your limits and failing, modern technology allows you to push further and further and survive and retain your skills, and this is a significant part of why the pure climbing skill of climbers today is so advanced.
The author has made the same observation but ignoring climbing technology and focusing on internet etc for spread of knowledge - but there are many skills that do not survive conceptualization and communication in tact, for those, you need specialist technology to advance your learning beyond the basics.
Go back 80 years, you will find weak, heavy hemp rope, rope harnesses that will probably kill you, and people literally carried rocks as gear, shoving them in cracks with the rope behind them. It's not hard to see how limiting this is in learning the skill, as you move forward in time gear becomes more advanced but still very heavy.