That set of people is not that small; it is basically what people in business analyst roles do all day. They know Excel very well and maybe even a bit of python/js, have a good understanding of the business problem at hand, but not technical enough to do full on custom reports from scratch.

Data Studio fits squarely in this market of tools for them, and that space is growing and pretty crowded. There a multiple big businesses built on producing tools just like that, for example Tableau (public company valued at ~10B as of today).

Granted, Data Studio is more basic but it is free and nicely integrates with the rest of Google data product suite (Analytics, Sheets, BigQuery). I don't think it will go away, and I think it is actually the strongest part of google cloud offering (and the biggest gap in AWS cloud product lineup).