It's baffles me then how a player can create fiction and also be acting in character. The two things seem mutually exclusive to me. Perhaps instead of ridiculing me you might explain your position.
"Barkeep, a flagon of your best ale," says Bob the Fighter's player.
GM: Sure, the barkeep busies himself with a small tun next to the main keg, and brings you a frothy mug, saying, "that'll be 5 silver."
Player: When he passes me the mug, I'll grab his wrist, drop a 10 gp on the bartop, and say, "and also any information you have on the whereabouts of NotBob the Vile."
This is in character, right? Fiction is generated, right? The difference in games is that in a GM curated game, what happens next is according to what the GM thinks should happen next. This might be in their notes -- they might have a note that says the barkeep knows something, and so they pass that on. Or, they might ad lib it, and say, sure, he's knows something, and pull out their notes about NotBob and pick a juicy tidbit. Or, they might decide this barkeep knows nothing, or lies, or calls for the bouncer... the point being that whatever happens, it does so according to what the GM thinks should happen, up to and include calling for a check and what the stakes for that check are.
In the games you're mistaken about, the above happens exactly the same way, but the GM cannot say no, they can only either say yes or go to the mechanics. On a failure, the GM is required to make the situation worse for the players -- no soft pedaling here. Something goes wrong. On a success, the GM is required to have the barkeep know something about NotBob, and it must be useful. Most of these games have a success with cost outcome as well, where the player gets something they want, but also something they don't want. The point being, the mechanics directly flow from the fiction, and the players can be as in character as they can be in other games.
Here's what this would look like in Blades:
GM: okay, that sounds pretty easy, so I'd consider it a Controlled action. However, that's a lot of coin for this area, and there are seedy types around, so let's bump that to Risky -- things could go sideways. But, since that is a lot of coin, let's say the Effect is Great -- you succeed and that coin will go a long way. What are you rolling?
Player: I'm rolling Sway, I have 2 dice, but this is important, so I'll push for a third. <rolls> A six!
GM: Great! The barkeep makes the coin disappear in a smooth motion, leans in, and says, "NotBob is in the private dining room through that door. He has 2 other guys with him, but they left about 10 minutes ago, don't know where, so he's by himself. You pay for damages." and he goes to the other end of the bar and ignores you.
The mechanical bits here really aren't any more intrusive that in a D&D game, where the GM calls for a CHA(diplomacy) check. The biggest difference is that the stakes are made clear, which I recommend for D&D games as well.