halving will occur this year, and that is one proof that bitcoin is still being developed, and the high price can also be proof. however, technology will always be improved, especially on the internet.
in the case of altcoin which exceeds bitcoin, you can expect it, and in the future, there will be coins like that, but for now, not a single coin has approached or can replace bitcoin.
This is not true, the halvings have occurred exactly when they were expected to occur and this hasn't changed since the beginning. The high price also means nothing, since it just means that current bitcoin is fine as it is.
No, if you want "proof" go take a look at bitcoin's code and the few changes it has gotten over the years. The "bitcoin core" developers have been maintaining the code for node and wallet etc which is something you can see at the very top "News: Latest Bitcoin Core release: 0.19.0.1" etc.