To be fair, they're not equivalent knowledge. Labs often imply equipment that cannot be gotten by normal means. Training and mentors know which knowledge is important, and sometimes possess knowledge that is hard to find because it's too specific and/or deep.

Research papers are a more obvious problem that is also easier to fix, but labs is nonetheless also a problem. Especially in fields where physical experiments are required, such as biology and chemistry, it's really hard to get anywhere without a lab, and running your own may be prohibitive and at times even illegal.