We should support altcoins simply because Bitcoin can't be used for everything. Does Bitcoin support smart contracts and tokens like Ethereum? Does it work as fast as Litecoin? Does it have completely anonymous addresses like Zcash? Bitcoin is far bigger than all this coins. They are all used for different purposes by different people. It is really hard to introduce an upgrade to Bitcoin because our community is big and has many different opinion on for example the block size or whether or not we should have introduced SegWit.
Yes we need to support the altcoins as there are many altcoins like you have mentioned which are specialized in something or the other thing and it will be really difficult to make any update or changes to bitcoin considering the size of community but we have to support and adapt to new altcoins with better technology and better features which could help everyone in future.