I think it boils down to what maps are comfortable to play. Insertion was interesting because it is kind of uncomfortable to be a T, there are no super relaxed positions because the CT's can pretty much come from everywhere, so the comfort is more with the CT's imo. The game's most played map is dust2, and I don't think it's because of nostalgia. CT's can hold comfortable positions, but at the same time there's enough map space to work with to employ simple and advanced tactics as a T.
I don't think any hostage rescue map has replicated this. CT's usually have to get to the hostages, which is pretty much like retaking a bomb site from a CT standpoint, and then they have to get to a secondary objective and watch out for lurkers. My thought to balance out this comfort is to try to make the T's a bit more in a time trap in the secondary objective. So they aren't able to run to one hostage zone and camp, but need to gather intel and perhaps gamble a bit.
We'll see if it works. But I think a very underrated reason to what is popular is the fact that there's comfortable things to do in a map. And it's such a fine balance, I think A on Nuke is a bit too comfortable for the CT's for instance.