Where the hell did all the steam accounts go?

I remember a time when this site was flourishing with 4/5/6 digit steam accounts... now it has seemed as if they have all dropped a long with the market.

This doesn't seem to be the only section that has been dropping.

I have been looking for days when it only use to take me hours to find a 4 digit and others are still looking for low digit accounts too.

My question is: Why is that?

Has the sellers with these accounts all been banned off? Or has the market for this actually just slowly disappeared?