I agree that this could be a possible explanation although it will mean that BTC vs ALTS have always a inverse relationship which is not always true. Some times both BTC and ALTS go down and some times both go up.

May be what you propose is part of the equation and you need to add also FOMO, FUD, news, rumours, adoption rate, etc.

In all I doubt that BTC will go down to $11.000 and even less to $8.000 even if I would like to buy some more "cheap" BTC.