I think so. I think younger users trust official branded apps a lot more so actually see the Reddit app as safer. Despite how easy tech people think lemmy and mastodon are, picking a server just isn't a feature to non-tech people - it's an obstacle to getting started.
The lack of content is a problem, but the lack of community feeling is the actual offputting part. Having bots repost things from Reddit kills the organic feeling of interacting with another user.
I'll probably be flamed but I do think having such a homogeneous userbase is negative. It means you don't get a wide array of experiences and viewpoints. People bang on about echo chambers online, but if you are in a club full of old white guys then you're in one!
I'd like think we can make these platforms as welcoming for everyone of all backgrounds, genders, etc, but there's just some things we can't understand without having those viewpoints being represented.