Is something "publicly available" if you can be sued for using it? That's the case for patented material for the 20 years before it expires.
There's a difference between the details of the invention being known and it being available for use. In the case of Google, it cost them $300M to license the PageRank algorithm because Stanford owns the patent (despite its inner workings being widely known).
To be clear, according to the supreme court, "It grants only the right to exclude others". So it's a misunderstanding to say "The entire point of a patent is to make it publicly available while funneling money to the patent holder". Sure, patents are often used to release details about an invention while making money off it, but that's just one use case. For example, it can just as well be used as an obstacle to slow down competitors.
"To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;"
I don't see anything about an invention being "publicly available while funneling money to the patent holder". The "exclusive right" part means the invention is legally the property of the inventor. Others can improve on it, but there is no guarantee the public can use the actual invention until the patent expires.
There's a difference between the details of the invention being known and it being available for use. In the case of Google, it cost them $300M to license the PageRank algorithm because Stanford owns the patent (despite its inner workings being widely known).