i am no expert to say anything about this "season pattern" that you are talking about here although my small experience tells me it doesn't sound true.
but this part is definitely not true:
which means no drastic bullish increases as it is too risky.
it is not a random thing that these big rises happen. it is because of combination of two things: 1. the small size of the market 2. the nature of adoption.
so far bitcoin adoption has been drastic and each time it brought a lot of investors in, in a short time. for instance last year during the $20k rally Coinbase was reporting 1 million sign ups in a couple of days.
add to that the fact that the order books are still thin and you will see these drastic rises AND falls.