The scalability issues are the main problem and the current market conditions are not as same as in 2017. BTC first time has crossed the $17k price and the altcoins have followed this route all the way up to ATH. The alt season will bring the big money to the market and BTC price has not reached the top level yet.
Altcoins will never follow BTC like they did back in 2017, you have my word for it. Of course some of them will surely go up together with BTC, but you'll never see shitcoins pumping like crazy cuz of BTC like the bullrun back in 2017. Solid projects will keep growing indeed, but having an "alt season"? Nah, don't think so. For reference you can check the charts of some coins which went up like crazy back in 2017 and as of today they're eating the dust with 0 movement at all.