re: Is tipping primarily a learned behavior?

It's a matter of perspective. For instance, I do not tip well unless I truly think the server did a spectacular job. I'm not tipping 18 or 20% for shitty service just because they're a waiter and that's what society has told me I'm supposed to do.

If they don't like relying on tips I suggest they either 1) become really good at their job, or 2) choose a different career path. This isn't indentured servitude, after all.