The dominance fell by 4% during the last two weeks, from 71% to 67%. Many of the altcoins have bounced back to important support levels (ETH - BTC0.0215, XRP - 2,900 Sat, Litecoin - BTC0.0074). There is obviously a sharp increase in the demand for altcoins. But I am not sure whether the trends will stabilize or not, because the IEO/ICO market is still looking very weak.
For the past 3 months, the Bitcoin prices have remained stable at $10K level. As things stand, there are not much chances of a breakout during the next few months. Perhaps for the next phase of the bull run, we may need to wait until the block reward halving in 2020 (which is another 8 months away). If profit booking occurs before that, the we can expect BTC to go back to 4-figures and the dominance to decline.
There are still some wild fluctuations in price across the crypto market. With this, Bitcoin's market dominance could rise or decline a little over time. But be aware, that Bitcoin's dominance will always be higher than that of altcoins because of many obvious reasons. After all, Bitcoin is the most trusted and secure cryptocurrency worldwide. It's the first cryptocurrency it comes to mind, when joining the world of crypto. Bitcoin may be not be as efficient as other altcoins are, but it has branding recognition, and most of all, censorship-resistance like no other. Those attributes will allow Bitcoin to remain as "King of Crypto" for a very long time.
Given how prominent Bitcoin has been lately, I wouldn't be surprised if it reaches a market dominance of 99% in the future. Only then, altcoins will control 1% of the market as they become highly unattractive among people in the mainstream world. After all, most altcoins lack true usability based only on hype and speculation. The 1% of market dominance will be largely attributed to big alts like Ethereum and Litecoin. The rest will be non-existent as we know it.
Nonetheless, with so many exciting features coming along for Bitcoin, I don't see why market dominance will decline in the future. On the contrary, it'll continue to rise slowly but surely as people become more interested into the pioneer cryptocurrency. Time will tell us what Bitcoin's fate will be for sure. But it seems that Bitcoin will remain in its rightful place in the market for years to come. Just my opinion