You say that if someone has the chops to be a real mathlete they won't need Polya's _How To Solve It_
I'll say I went to college 25 years ago with people who had competed internationally in high school and who placed competitively on the Putnam, and they LOVED Polya's book.
I think whether you enjoy seeing strategies laid out well--—whether or not you've been able to figure some of it out yourself---depsnds more on your personality than on how good you are at solving creative math problems.
Depends on required features like cross browser support, cross device support, handling pdfs, ocr images, etc. Some of the mentioned features already exist in the browser. Not sure if the browser vendors are incentivized to develop and maintain such features.
If it were easy/cheap enough to host, can a model like shared game servers or web/email hosting work? People pay $20 a month without thinking for web hosting. What does it take to make "search hosting" a thing, where cheap search hosting companies can crop up both at the low end with bare bones offerings and others climb up the value chain with offerings like squarespace...
HN continues to pay lip service to wanting to make this better but does NOTHING to move the ball forward. Simple things like providing barrier less access to HN content and harder things like crawling all content linked from HN would be a great resource to bootstrap new search engines.