If you are not implementing heat training are you leaving performance on the table?

Kind of? In the first study trained cyclists in the heat group saw significant gains in what was basically 2 weeks/10 sessions of work.

Sure, many people are time constrained but maybe the gains are worthwhile? They saw a 5-8% increase in vo2 max and TT performance increased by 6-8%.

I would not think many other 10 session interventions would have the same impact, especially on already very fit individuals.