Bitcoin's dominance will organically decrease depending on the site that's calculating the percentages.

If we look at CMC for example, it's not so much that altcoins haven gained on Bitcoin, but more so that the quantity of listed altcoins has increased. If you keep adding altcoins, which happens continuously, the dominance will eventually drop below 40% or even below 30%.

If you also add that altcoins are somewhat leveraged Bitcoin products due to their similar but exaggerated movements, there isn't much that you can do here. Bitcoin is very long term bullish, so based on that, even the most rubbish coins will gain value throughout the years. Welcome in the world of crypto.

The worst part is that you can't even short 99% of the altcoins. Up is the direction.