Most of which are rare in the games industry but seem to be very successful in the web industry.

HTTP is also successful in the web industry. Perhaps game programmers should use it to pass around all their information.

Less snarkily, there is a reason why those things are popular in web development: they're good at it. There is a reason why C++ is used in game development: it's good at it. High-level languages are commonly used in scripting and game logic, but, if used in the engine, would slow it to a crawl.

With respect to "deploy, measure, iterate": I have a suspicion that such a methodology isn't entirely feasible in an industry that ships product in the literal sense of shipping product. It's easy enough to do A/B testing on a website. It would be a touch more difficult to do it for Half-Life, given that the install base is approximately everywhere and you have control of roughly none of it.