Shalom Meckenzie made a $1.4 billion fortune after merging his software company with DraftKings. He now believes his new fitness company, Amp, could be even bigger—just don’t remind him about Peloton. Or Mirror. Or... Mekenzie isn’t the first one to think there’s a big business in at-home workouts: Amp’s business model is nearly identical to that of a slew of failed and struggling exercise companies like Tonal, Peloton and Mirror: Sell wealthy folks an expensive machine, hire a bunch of