I kind of disagree. I think that, once you start using a crutch, you're almost certainly never going to stop, especially in a perceived-risk-high situation like public speaking. "Info-dump slides worked last time. I'll go with what works again, rather than adding risk by trying to be more minimal," repeat ad infinitum.
It's better to recognize that you just didn't prepare enough (didn't practice sufficiently; didn't know your subject well enough; didn't anticipate questions and concerns; etc.) and prepare better next time.
It might be a little different in a teacher-student environment where direct guidance is possible and disasters can be coddled and mitigated and explained away as "this is a learning environment; screwing up is okay". Just... don't grade it.
Well, it depends how much you care that your talk was a disaster.
For people who are not practised at speaking, there is almost no amount of preparation which will get you to the point of needing no crutch. Not knowing your subject well enough is not excusable, but many people who can happily explain a topic in a one-on-one situation have great difficulties in front of crowd.
Of course, there is only one way to get better a public speaking, which is to do as much of it as you can.
I don't understand your 'teacher-student environment' comment. Are you suggesting 'coddling' encourages, or discourages, giving talks with less crutches?
It's better to recognize that you just didn't prepare enough (didn't practice sufficiently; didn't know your subject well enough; didn't anticipate questions and concerns; etc.) and prepare better next time.
It might be a little different in a teacher-student environment where direct guidance is possible and disasters can be coddled and mitigated and explained away as "this is a learning environment; screwing up is okay". Just... don't grade it.