Bitcoin has a limited supply and as far as buying continues to exceed selling by very high merging which is already happening, demand will always be higher than supply. On the long term scarcity will always make the price to continue reaching new ATH.
It is one of many contributors to Bitcoin value but if Bitcoin only has a limited supply, it does not have high value. Bitcoin has other things like decentralized blockchain that is Proof of Work, very secured and has never been hacked or attacked 51%. Bitcoin blockchain is also censorship resistant and all those things contribute to its high value.
You can find many altcoins with limited supplies that are even less than Bitcoin total supply but those altcoins already died or have very low prices on the market.