Life is a mixed bag, and so is comparing the past , present and future of this hobby.
The models were cheap back in the '60s, compared to now. But nobody make as much money back then as they do now. Dick Radditz made about $60,000 pitching for the Red Sox back in 1965. And he was paid well.
Model kits were modified promotional models back in the '60s. Nobody would accept that level of detail in today's kits. More scratch building back then.
It isn't just inflation that pushed the price of the kits up. It is volume of sales (economies of scale, no pun intended) and promo business helped pay to design the basic kits 50 years ago.
The kits today are very nice. Less extra custom and additional parts, but fit and detailed better than the old kits.
There will always be models. I doubt 3D printing will kill kit manufacturing. Prices will rise, but who knows how much.