Boomers are not passing their businesses down
A lot of older small business owners treat their businesses like a retirement plan that will give them a big payout when they decide to step down. They don't want to deal with loans and they want a large lump sum payment. But then they sell their small business to a private equity firm that will draft off of the reputation the business had under the previous owners while cutting corners in quality.
On the flip side, amongst my peers, very few people see "starting a business" or "running a small business" as a viable career path. The implicit assumption is that the only way to have a stable life is to work for a large corporation. And to be fair, trying to start a company is a herculean task. It isn't for everyone, and the majority of people are going to be disinterested in this level of risk taking.
However, I suspect the reason young people aren't pursuing more entrepreneurial paths is because they don't see success as possible, not because it is hard.