I've heard that Bitcoin will finish mining in 2140, which is certainly a long way off. There's still a chance for us to continue dca BTC, as there's a strong possibility that in the future we'll see a higher BTC price than today, as BTC is constantly being mined, and we'll eventually see the BTC supply dwindle. Currently, I know there's only a small amount of unmined BTC left, approximately 1,100,000. While the number currently mined is 19,900,000, there's still time to accumulate BTC.
BTC being mined constantly isn’t a factor that guarantees for it’s price increase, in fact, it’s supposed to bring about price reduction due to the availability of Bitcoins in the market, that’s in the event of miners having to sell their rewards, providing liquidity.
Bitcoin’s valuation comes from scarcity, scarcity that is only prompted by demand and supply. When it’s scares people tend to pay more for what’s available, it’s the law and the limited Bitcoin supply with a growing Bitcoin adoption in a populated world ensures it.