Well, it's a complicated question to ask, everything has two sides to it. Are all youtubers/viewers supportive? No. Are most of them supportive? Probably not. Is there a majority that does as much as they possibly can? I do believe so.
Everyone gets haters, and the bigger they are the more haters they'll have. Bigger tubers helping smaller ones is a perspective issue, there's plenty of say 10mil subscriber tubers collaborating with 1-3mil subscriber tubers, but do you consider that as helping out smaller tubers? Or just friendship between people with "large" audiences.
I do think there's a lack of people helping out less fortunate viewers, like in the past pewdiepie used his #1 spot to hold a contest and out of it we got jacksepticeye, that was an amazing decision by someone with a large following giving back to the community, personally I don't see much of that anymore, there's probably a lot of really amazing content creators that go completely unnoticed due to youtube algorithm and simply not having any support from the community. Not even saying that as a creator myself, I'm just a tadpole in a big pond, I know I have a way's to go, but someone that's been at this for a year, or two years, maybe even longer with hundreds if not thousands of good videos going completely unnoticed is a possibility.
But I don't know, I do find that there's a lot of people that want to help, with feedback, with criticism, etc. Maybe even mention your name in places. There could be more, but at the end of the day the people themselves decide whether they want to help out or not.
Me personally if I had a following of people who turned to my content for entertainment and were so supportive like all the big tubers have I sure as hell would be giving them exposure whenever I could.