I knot you’re not OP, but and while this explanation is good, it doesn’t make sense to frame all this as a “problem” for parquet. It’s just a file format, it isn’t intended to have this sort of scope.
The problem is that the "parquet is beautiful" is extended all the time to pointless things - pq doesn't support appending updates so let's merge thousands of files together to simulate a real table - totally good and fine.