I dont think a bitcoin bull run will be driven by ethereum. There is no reason to think that they would be tied together. If anything it will be the reverse, it will be a massive bitcoin run that will drive the next eth run if at all there is another ethereum run.
Exactly. Bitcoin is the one cryptocurrency which moves everything on the market. Once there's a bull run on Bitcoin's price, you can expect other altcoins to follow (not the other way around). Ethereum being the world's second largest cryptocurrency by market cap, still depends on Bitcoin to survive. Since the pioneer cryptocurrency is the reserve cryptocurrency of the market, altcoins either go up or down in price alongside it. Bitcoin's upsurge in price would allow Ethereum to reach new ATHs across the crypto market. But first, it would need to scale with the adoption of Casper PoS and Sharding. Otherwise, people won't have much interest into Ethereum after all.
Once this happens, we could expect the price of Ethereum reach at least $1,000 within a 1 or 2 years from now. After that, Ethereum could rise even further in price as mainstream business and companies launch their own dApps within it. The goal of $2,500 per ETH may not be farther than we've imagined if the aforementioned events take place in the future. Still though, no one knows what the price of Ethereum will be over time because of crypto's volatile nature.
Which is why, there's a possibility that we'll end up waiting for Ethereum to rise towards astronomical levels in price, longer than we've thought. As long as you buy more Ethereum while prices are still low, you'll be able to secure your profit in the future. Combining ETH and stablecoins seem to be the smart move nowadays to survive in this bear market. All in all, Ethereum will be here to stay no matter what its price will be within the future. Just my thoughts