cause you will only have a basic skill in it.
sorry but I wouldn't hire you with a basic skill when I could get younger people that have the same skill and will probably learn faster.
if you are advanced in your skill set, than I will hire you probably depends on how you act, but just saying "I can learn any technology." is pretty naive. maybe you briefly scratched an egg of the technology but you are so far behind the others that we could get pretty reasonable other people.
You should really focus on stuff that you are doing else you will never master anything and be a junior all the time.