At first, I thought providing training was a good idea then as a former trainer on tracked dozers and rubber tired dozers, I have re-thought this. We all see the stickers on the new units we buy as well as the operators manual that goes into pretty good detail as far as hazards while operating machinery. Reading them and understanding them goes a long way towards safe operation.
The most common complaint that came back to me after someone got themselves in trouble with a piece of machinery was "I wasn't told about that in my training". And to top that off, they were usually the ones that didn't ask questions while being trained. I really don't think a dealership want's to take on that kind of liability in my opinion.
I understand what you're saying and there's a couple of simple ways around that.
Using the motorcycle example; the dealership that I bought my bike from (years ago) offered a "Maintenance Night"... come to their shop and the mechanics would show you everything to do for simple MC maintenance & fluid changes. It was something like A$30 and pizza/soft drinks were included. It was information only, a familiarisation.
The other example has already been mentioned, HONDA (and other companies) have closed track facilities where you learn theory & practical skills (taking turns, emergency braking, starting on a hill, etc...) They have one course that you can take prior to going for your full license (also helps you to
pass that test) and an 'advanced' riders course that anyone can take to sharpen up their skills. The Navy actually payed for me to take both of those courses, which was nice, but I would've taken them anyway.
They were not mandatory to get or keep your license. They provided knowledge only; it was up to you to practice & apply it therefore, once you were off the provider's facility the onus is on you.
As I've already said, a previous forklift/material-handling course's
knowledge and practical experience was easily transferred to my tractor & FEL operation... low & slow.