"If I had the money of Bill Gates, I'd take the Everest helicopter design and scale it up with a bigger supercharger so it could carry significant payload to the top of Everest. Then on top of Everest, I'd build a concrete viewing platform with guard rails, two picnic tables, a BBQ fire place and a rest room with running water." Etc

And people would probably hate you. And probably dynamite the whole thing off the mountain:).

If I had Bill Gate's money, I could think better ways to spend it.
But if I wanted to get stuff to top of Everest, I would use a balloon*. And I wouldn't use concrete- it would nightmare using premixed and mixing the stuff up it there won't be easy. Then you need the forms built and probably require the whole thing to be tented in order to pour it.

Of course the summit is covered in ice and snow and getting down to bedrock wouldn't be too difficult, but I imagine anything put up there will be encased in ice and snow- in other words your deck would become a block of ice, and unless you keep your BBQ on constantly, it too would become a block of ice, and finally your shed with "a rest room with running water" would also become a ice block. Of course Everest isn't known for good weather, so there wouldn't be many days of the year that this rest spot could be used and during the summer season one might only need to *seriously* de-ice the stuff once per year.

* I believe balloons have lifted 5 ton payloads to around 100,000 feet, so lifting 5 ton payloads to 30,000' should be possible but you need a system to control the Balloon- which would probably involve using very strong light weight cables. Or suppose you drop the balloon idea and just use a cable- tram system. Windy days would serious problem though.