Had a discussion about something similar. “Why don’t we take all the energy created in fitness studios? People constantly push pedals there!”

It’s just so phenomenally little it doesn’t make any sense, a full routine wouldn’t even full charge a smartphone battery (not even close). Put solar on the studio roof instead.

I’d assume it’s the same with these. Apparently the idea was even abandoned when it was applied to cars on highways, even those don’t produce enough energy by driving over it to justify resources and maintenance.