Risk / return trade-off still holds - great insight!
Performance through-the-cycle is a big question. One can point to Salesforce (founded 1999, IPO 2004), which has been around for 20+ years... However, big sample bias here (ditto for my article, with sample n = 1). Salesforce, a big-category-defining company - may not be representative of moderately-sized businesses.
Whoisnnamdi - per your post, revenue retention looks like a key metric driving valuations!
Being (1) private, and (2) moderately-sized, allows you to adapt more quickly - same reason why buyouts of public companies usually end with delisting.
Useful thing in a downturn!