Prediction has no limit but we should think about the limitation by analyzing marketcap and others factor. Dogecoin is meme coin and it is literally impossible to hit $20k because there is no progress and future of dogecoin in day to day usage. Yeah it can possible if you buy a single dogecoin by yourself with $20k.
To say it, let's just all agree that there's a possibility that it can reach that price, thanks to the volatility of the whole crypto market. But we do understand the economics of cryptocurrencies just as you've said about analyzing the market cap of it and the factors like the supply and demand. We knew it's impossible but just for the sake of speculation, argument and prediction, let's all agree with that but we're sure that we're not going to see $20k for each dogecoin.