Musk has a singular goal as far as I can tell: to make humanity a multi-planetary species. All of those things are testing the boundaries of what's possible in areas that will or could be very important for building a permanent settlement on Mars.

I posit that while there's much room for debate around whether or not those projects are viable, as far as I can tell everything Musk has done has been in service of building the corporate framework, talent pool, skills, and technology necessary to colonize Mars.