It doesn't really work that way, there is no existing code base to check and tell you what addons may or may not conflict with another, at best you get an error message when you get one and have to hand it over to someone else who either already knows or has the ability and time to sort it out. On top of that, you now would require that all people who make things for others (for no other reason than they want to and many time for free)... to possibly change the entire structure of their addon as well as add a whole bunch of other code to come close to the features of an easy installer that you describe.
Most developers I have met in my life, are self starters who work for themselves and define the working parameters of their day on their own, a system like you imply would literally force people of free will to either work a certain way or leave and in the end this will cause a loss for the entire community.
Make this consideration, if updating an addon is such an arduous task, imaging what it takes to make that same addon from scratch and support it and then be asked to rewrite the entire thing so that one of the two steps someone must take (generally speaking) to use it can be done instead with one click. A system like that would be more of an impedance than a turbo and would slow down development even for the most trivial of addons/modifications.