My two cents on IG mostly.
Accounts that are easy to grow are not easy to monetize therefore people sell them here. Quotes, meme's etc are easy to grow but you get such a diverse following it's not easy to sell one thing effectively that interests everyone.
I see a lot of accounts here where people list the niche as fitness, or tattoo's but really it's just hot girls in skimpy clothes that are fit and they call it fitness, or tattoo's and the girls are hot. Most of those followers aren't interested in tattoos they want to look at hot girls, it's not like they are going to buy tattoos from someone on the account.
Large followings of inactive followers imo is worse less than a smaller following of active accounts. I make more on my accounts that have 20-40k active and we'll targeted accounts then the generic 100-200k accounts.