The whole point of a tenure track position is to show that someone can independently work and lead a laboratory.

An academic career is extremely slow compared to most other careers, so i don't know why would automatically assume that people 10-15 years of research experience, typically in their 30s-early 40s cannot work independently or cannot supervise 5-10 other people. The old system you mention typically degrade most assistant and associate professors to a low level administrator / secretary position.

The whole point of a tenure track position is to show that someone can independently work and lead a laboratory.

An academic career is extremely slow compared to most other careers. I don't know why anyone would automatically assume that people with ten to fifteen years of research experience, typically in their late thirties or early forties, cannot work independently or cannot supervise five to ten other people. The old system you mention typically degrade most assistant and associate professors to a low level administrator / secretary position.