I am not sure that is a bubble for bitcoin knowing the fact halving happened this year. Most probably to see an altseason would be in the spring of 2021 if we are looking back at 2017 chart
depending on Bitcoin, if bitcoin at the end of this year reaches a new all time high,
I'm sure 2021 is altcoin season, but if not, then we will wait even longer for the altcoin season,
whether this will happen again or not.