Commercial libraries = private library where you pay a membership fee? I’ve not really heard of that here outside of arguably university libraries and similar.
But SF public library has a couple dozen branches or more?
Yes. I had a membership for years. The place looks 19th century, which it is. There are multiple levels of stacks over two floors, carved dark wood, comfy chairs, and librarians who scold anyone who talks.
Members can go there, plug in a laptop, and type. Quietly. It's never crowded.
It's a well-curated, library. It's most useful if you want historical information about 19th and early 20th century technology. They have a complete bound set of Popular Mechanics, from the days when it was a serious technical publication. The multi-volume engineering study for the Panama Canal, with drawings, is there. Current offerings are well chosen and updated regularly.
Yes, the one I went to as a child had a monthly fee and a per-book fee. It had a far more extensive collection than the SFPL library at 4th and Berry in a much more compact space. Most SFPL libraries appear to be homeless-support centers, which diminishes their capacity to carry books since they assign greater room to support functions. But perhaps that is the source of the value observed in the OP.
As an aside, are there university libraries one can join directly for a fee? I was under the impression they were bundled in with tuition etc. If it’s around $100/month I wouldn’t mind that, but perhaps that is an unachievable target.
One thing worth noting, these accesses do not always include access to electronic resources. Access may only be available from computers that are in the library.
Personally I've never heard of or been to any commercial library before, perhaps it's really good startup idea with internal coffee shop (library first, cafeteria second).
I've been to coffee and books cafe (basically cafeteria first, library second) in France and normally it's full during the day (close at 7 pm).
In the US, there are some private archives. And university libraries with varying degrees of public access somewhat depending upon the degree that you can walk in and look like you belong. But real public libraries don't generally have a lot of restrictions.
But SF public library has a couple dozen branches or more?