[tsimionescu]

How do you decide which researchers to invest in? Ultimately you need some kind of institution to organize this, and I promise you it will end up very similar to a university.

Also, tenure is generally seen as a very important part of research. Without tenure your livelihood is dependent on your output and your relationships, which creates numerous perverse incentives. You can't research things which might lead nowhere, or you'll lose your job. You can't prove some other senior researcher wrong, or they might work to have you fired.

With tenure, this all goes away: you are free to choose your own path in research, and empowered to know you don't have any superiors who can lose you your livelihood if you step on their toes, or their friends' toes. Of course, this is the ideal. In practice, lots of tenured professors actually want to become ever more wealthy and powerful and are not content with the guarantees of their tenuership.