Arguably a language issue. What exactly is the threshold to be called "bowling expert"? You apparently consider the knowledge to regard the difference as obviou

Arguably a language issue. What exactly is the threshold to be called "bowling expert"? You apparently consider the knowledge to regard the difference as obvious more baseline than expert, perhaps not even considering anyone "expert" who wouldn't feel at home commenting bowling on TV. Perhaps that threshold isn't all that unreasonable in American English (no idea how widespread the game is over the demographic spectrum). But there are plenty of people who'd consider baseline bowling knowledge to know that it's a game where you throw a ball at pins and if you can correctly name the number of pins you're already on the threshold of beyond baseline. Yeah, technically you might still name levels of expertise below "expert" that would clearly see the difference, but that's not how the term is colloquially used. From the baseline perspective, shades of expertise are experts-only. In any field.