The coffee person can't charge proportionately because coffee delivery is oversupplied with potential vendors. Look at training that way.
You're not going to make a high rate if you're "a Python instructor", because there's quite a few of those.
You will if you're "the you Python instructor", and the customer thinks you're worth that rate, because having their people trained by you is worth the premium.
And that's where testimonials, referrals, previous track record, etc. come into play. Selling that version of you to a customer.
And granted, some of them won't ever be interested in that. They just want a Python trainer at minimum cost. But if you can afford to be choose and pass on opportunities, the higher end work is out there.
