Instagram differs from Reddit in the sense that most people use Instagram because that's where their friends and family are. You're posting more personal things there. An alternative doesn't really work for most users if no one they know is using it. Good luck with the push, though.
Yeah this is the issue I have. I wouldn't even be on instagram if it my friends weren't on it. Pixelfed has a much tougher road to snatch users than a place like Lemmy or even Mastodon for that reason. If everyone I know hopped over with me (which let's be real, I would never be able to get everyone to do that because they would run into the same issue with their own friend networks) then i'd gladly move over.