As you an see in above chart bitcoin dominance has broke the previous side way trend and now journey started towards a lower level side way trend as you can see since the ATH, btc dominance is falling down step by step altough steps are small but putting major impact on price. It seems hard for btc to reclaim new previous upper level dominance. I think if btc dominance fell below 67.36 even lower level after going few days in side way it might start alt season. During that time BTC will fell below the $8500 support and the next support will be around 7.5k which can boost the dominance again.
Please Note: I've plenty of things to explain but because the lack of English language knowledge I can't explain. Don't mind my mistakes :)