Investing in altcoins may make sense when the dominance is at this low level. But it can be just as risky. Because in the near future, bitcoin dominance will be on the rise.
$ 20k is indeed the range that can earn some bitcoins. however, I might choose to hold ethereum over bitcoin. I know that bitcoin has less risk than others and also a higher profit rate, however, I am pretty sure that Ethereum can get a 0.1 BTC / ETH pair range. So, if you have it for $ 20k at the moment, I think the benefits could be bigger.