Early access is extremely effective, when used correctly. It lets smaller studios get an income stream a lot earlier, which helps significantly. It also lets them form a tight feedback loop with fans. They can find out what works and what doesn’t. Some examples of it working well would be Rimworld, Kerbal Space Program, and Factorio. All released as amazing games, primarily due to early access.
Unfortunately, a lot of companies seem to be abusing the idea right now. Particularly bigger studios.