Given how dependent Apple's devices are on wi-fi, I'd love to see them invest in building out real, full-coverage wi-fi in the top 10 U.S. cities available for free to any Apple device.

Getting into the cellular game seems like a mistake, but investing in wi-fi "towers" to side-step cellular companies seems like a win.

Especially when you consider the investment Apple has already made into web services that side-step the cellular establishment (iMessage, FaceTime, iCloud, Push Notifications, App Store, etc). They don't need cell towers, everything works on Wi-Fi.

Or they can simply keep making money with LTE / G4 without any investments?

Trust me, I agree with that more than anything. I don't want to see them spend money on anything, really, if they don't need to. More wishful thinking.. :)

I always wondered what apple's plans were for the next 10 years.

The iPad is close to perfection, the next iterations surely will improve but only slightly and in maybe 3 or 4 years most people won't need the newest device anymore.

The same will be for smartphones in a couple of years, the limitations will be in the speed the carrier provides.

It absolutely has to be the living room. And domination of the laptop market.

http://www.alexmuir.com/2011/12/apple-must-build-a-console/

There is no shiny in that. Apple is about making the shiny.

I don't mean that as a negative comment - they are about making shiny easy to use products and an ISP is not that.