On Twitter I have 774 followers after 12 years of use, and on Mastodon I have 538 followers after only 3 or so years. I post the identical posts to both networks at the same time, and respond on both. Yet I see noticeably more engagement, queries, comments, etc on my posts at Mastodon. This poll had 136 votes on Mastodon but only 25 votes on Twitter. It got 12 reshares on Mastodon and 1 on Twitter. Both polls had the same hashtags and #DeleteWhatsApp
was very busy on both networks.
My theory is that on Twitter an individual's posts get largely drowned out by adverts and promoted posts, and of course the algorithm that shows "top posts", whereas on Mastodon users only see who they are following giving more visibility to a user posting...