I was lucky enough to get a 3 character Instagram handle back in the day. I get 5+ password resets a day and frequent offers for it - the most I've been offered is $25,000 for it. It's a pain.
There are probably people out there with spreadsheets full of service types, account names and passwords of accounts they control that include all the two letter to four or five letter company names, and many celebrity names, just in the case that someone wants to pay for it. The domain name game, just evolved for the current climate.
I mean, it would take me less than $25k worth of my time to build something to automate this, even if I had to get rotating IPs, mobile accounts, and have mechanical turk to solve CAPTCHAs (although with all those features it might be close), and you were offered that for one account.
Also, I don't want to be out of it if they report to Instagram that it's for sale etc.