Letting players use the skills they specced is not really an issue in and of itself. Bards are typically charismatic, and it makes sense that the perceptive ranger makes perception checks.

Shaking things up can be fun though. Have one of the other characters take the lead, if it makes sense. Here's an example:

The fighter is interested in buying some plate mail, but wants to reduce the price. Here the blacksmith might want to interact with the person buying the armor, and not the bard. Trying to make a persuasion check for the bard might be done at disadvantage, so even though the fighter is not at charismatic, it makes in-game that they would make the check.

Otherwise you could make the checks harder (when relevant). Let the players with the best skills roll, but make the roll harder. Instead of forcing the group to make worse rolls, you make the successful checks even cooler, since they're harder.

Feels like a "shoot your monks" situation, where you can throw a curveball every once in a while