Yes it is threatening the bitcoins value.
There is possibility of bitcoins become useless . Because of so many altcoins the we can use instead of bitcoin and more affordable than BTC .
I do not think so. The huge number of different cheap tokens is the proof that no one of them can ever replace Bitcoin. They are not a threat for the cryptocurrency #1.
Yes, because bitcoin is the foundation of all the coin in crypto market and since it is the first most accepted coin in crypto market and until now its popularity are continually spreading world wide, its true that there are a lot of new born coin but still they can't beat bitcoin, by the value alone they have no match to bitcoin.