Asset creation is indeed part of the problem, but another part of the problem is scale. Take a title like Resident Evil - it's fully feasible that a team of under 20 people could make the game, if they were dedicated and could source outside talent. One person can do texture work/game art, one person can do the music and pretty much everyone else is working on asset production or programming.

Think about how that's scaled up in the past two decades, though: https://www.youtube.com/watch?v=arEdruKxrQ8

Game development really is a whole different game. Not only are you making higher-resolution assets, but there's often a greater demand for variety and detail. Resident Evil's debut has a fairly limited palette, mostly combining cityscape textures and simple gothic/wooden architecture for the indoor segments. Resident Evil 8, on the other hand, takes place across 5 or 6 unique locations, all with their own unique styling and trappings. First-person perspectives demand well-educated firearm experts to tune every polygon of gun geometry. High-resolution assets require dedicated artists to give them filigree. Nowadays, games are built by teams of specialists who each have a little something to contribute. My favorite example comes from a teacher I had in high school, who was married to a motorcycle engineer that exclusively worked on video game assets. Apparently he had no shortage of work, and I don't doubt it.