Why Indeed? My general guess is it was a way to not be 4e? To conform to elements of an earlier edition? (1e and 2e I think and maybe 3e to an extent) that kept mundanity/non-magic under lock down. 5e designers said they wanted low level things to be challenging for much much longer and that is for the most part what bounded accuracy achieves. Its worse for skills than combat because skill obstacles lack hit points (another arena of advancement beyond the check).Why? Why can't you have a rogue that is so good at picking locks that they're the only one in the world that has a good shot to pick the Lock of X'elios without magic?
That is a good story element. That makes the heroes feel like they stand out.
The underlying belief when we say that Expertise/High skills ruins the game is that character success on most, if not all, skill checks of a certain type is inherently bad. It absolutely is not. I've had the rogue in my game that could hide from anything. I've had the silvertongued devil that coud convince someone of almost anything. I've had the barbarian that could bend things thought to be unbreakable. And it was awesome. The players enjoyed being a Herculean style of awesome, and their exploits were legendary.
If, as a DM, you're frustrated that you can't challenge players with certain things, or that they can 'too easily' do certain things... really consider why that is a problem for you. If the goal is to tell a good story, why can't you use that story element as something to celebrate and applaude? A lot of our iconic myths are about people that can do amazing things - and they're not all wizards or using magic.
There is also an overall competence loss in 5e, the 4e hero got better at things by being around and learning from allies and gaining general confidence and probably adaptability if you want to think of it that way. 4e assumed there was learning going on that didnt have a big tick mark and name next to it so all adventuring skills got better. My late paragon chosen one of the goddess doesn't have to worry about getting passed the town mayor even though she doesn't specialize in social skills. It is perhaps a different related issue.