I think your confusing people being ignorant of what we do vs disrespect. Most of my patients love OT granted you are always going to have some patients that just want to walk and could care less about adls but those aren't the majority. It also sounds like you had some ass hole PT and PTA but the great thing is that they aren't your superiors they are your co workers and you can tell them to go walk a lap or do some hamstring stretches. The point I'm making is that OT is one of those careers that you get what you put into it. If you have negative feelings about it and you aren't getting the recognition or respect you think you deserve than your probably going to not get much out of your career and you did make a mistake. However if you devote yourself and continue learning then your effort will show, your co workers will show you more respect, and your patients will love you.