Before convincing ourselves that duration determines the seasonality of a trip, we must anticipate the exit conditions.
Shortening a trip for budget reasons doesn't force us into the low season; it's a strategic choice that involves risks.
For example, wanting to see the sakura in Japan requires a very specific time window, regardless of your stay's length or your budget.
If you're seeking the cherry blossom experience, leaving in low season to save two weeks will make the goal unattainable.
The mandate is to live the experience, not just to save money.