We now have new set of investors and the catalyst now isn't the same with the previous bullrun. We now have more experience in the market as Institutional investors are coming in in their numbers meaning the market is soon to be more mature and stable unlike 2016 that we had more in inexperienced investor and speculators.
Now we have NFT and DeFi projects front running the bullrun that's because they're the trending technology right now. When it comes to altcoins they have their season to trend. The old coins are still great choice but don't expect same results with trending project.
When it comes to altcoins bull run,, you can always go with the flow but apply cautious unless you're investing for long term that's when you don't have to care about the pumps and dump as coins are likely going to dump ones the energy die off.