Is the "free trial" model dead? Or just bad?

Lots of academies advertise "first class free". My experience as both a student and now a coach: people who do free trials convert at way lower rates than people who pay $40 for a single drop-in.

The paid drop-in selects for someone who's actually serious. The free trial selects for someone who showed up because it cost nothing.

Anyone tracked this at scale? Or is this confirmation bias on my end?