@Michael Baum when someone doesn't have experience, the confidence level comes from the comps in the area. If you know this is a strong tourist market based on the number of listings in the area, you're going to be much more confident that you can replicate success than if you were starting from scratch with very few comps.
As you start investing in more STRs, then your confidence level is not only based on the comps in the area but also your own experience level. When someone is starting out, they should not have a high confidence level in the revenue potential of a property unless they see comps that their property can beat out.
I agree, an inexperienced investor may be unrealistic in their confidence level. However, once reality hits they'll learn from their mistake and adjust their confidence level for the next property accordingly.
And I'm sure you'd agree you wouldn't have much confidence when you first invested in your lakefront rental if there were no comps at all :).
If you want more on this concept, definitely recommend checking out a great book called Thinking In Bets. Hope this helps!