At least 3 crypto-currencies today have high chances and real tools to outstrip bitcoin by capitalization in 2018.
ETH - has scaling issues aswell, but yes, it can outstrip bitcoin by market cap (not like anyone cares about market cap except for crypto newcomers)
Ripple - centralized bankers shitcoin that goes against the fundamentals of cryptocurrencies and what they're based on. Obviously, Ripple has a high chance of getting the #1 spot by capitalization, but not because investors are interested in Ripple, but because the circulating supply represents 40% of the total supply, so if the team behind Ripple decides to release 20m XRP from the total supply, its market cap will instantly go up without needing the help of investors.
Stellar - a project with potential that is playing the long game, the main problem is the unreleased supply, it's worth mentioning that Stellar devs own 80% XLM, so if the devs decide to release all those lumens little by little into the market, it can become a serious issue for investors. It can go above Bitcoin by capitalization, then again, does it matter?
"Time is running out"? this sounds completely biased, I can say the same thing about time running out for altcoins because Bitcoin is going to implement lightning network, and SegWit widespread adoption will reach its peak, which is going to make Bitcoin bulldoze every altcoin in the market.