The next bull run could see a mix of dominance by both Bitcoin and Ethereum, along with a surge in promising altcoins. Historically, Bitcoin and Ethereum tend to lead the market due to their established trust and widespread adoption. However, altcoins often outperform in bull markets because of higher growth potential and innovative use cases, such as DeFi, NFTs, and Layer-2 solutions. The extent to which altcoins drive the next bull run will depend on factors like technological developments, partnerships, and community support behind individual projects.