You hit all the right points.
On the last point, with so many avenues that can be used to gain/collect information its nearly impossible for the individual player to "stay ahead" of or even match the data the books can obtain. They have seemingly unlimited resources. Its like a futile effort to make the attempt... but we continue to try.
you are right, we find an edge in only having to play a couple games, they play them all, they are playing for razor thin margins and the gambler is playing for the big win, gamblers make mistakes in that process, the level of information and experts they have in their database is large, you have to exploit prop and player markets and smaller markets as well, ultimately they also control the limits on you which will contain you