It looks quite difficult to get into that phase again, now we can see where BTC dominance is already very large in the market, I think ALT season will come when BTC dominance decreases maybe in the range of 50%, so you can estimate if BTC dominance decreases meaning ALT season will appear soon.
Yes. That sound right. For now, bitcoin has too much dominance over market. Altcoins haven't given big returns from last 1 year or so that's why, investors are investing in altcoins less and moving towards bitcoin completely. Size of their portfolio is decreasing and becoming homogeneous with bitcoin. Only if bitcoin decreases too much or alts rise too much when people's interest will transfer towards alts again.