Seasons that once ran twenty-odd episodes now frequently run eight or ten. The change follows from how shows are commissioned and paid for rather than from any shift in what audiences will watch.
The broadcast schedule set the old number
Traditional television had a calendar to fill. A network needed a slot occupied every week across a season, and the episode count fell out of that requirement.
Advertising was sold against those slots, so more episodes meant more inventory. Volume was the business rather than a creative preference.
Streaming removed the slot. Nothing needs to occupy Thursday at nine, and there is no weekly inventory to sell, so the number became negotiable.
Spending moved from volume to the hour
Budgets did not simply fall. They were redistributed, with far more spent on each individual hour.
Location shooting, effects work and longer shooting schedules per episode all raise the cost of an hour considerably.
At those rates a long season becomes unaffordable, so the same total is spent on fewer, denser episodes.
Film-level talent works on film-level schedules
Shorter runs made television viable for actors and directors who would not commit to most of a year.
A ten-episode order can be shot in a window that fits alongside other work, while a long order effectively claims a performer's calendar.
Once shorter runs attracted that talent, the format reinforced itself, because the shows people wanted to make were the ones built this way.
Release patterns changed what a season is for
When episodes arrive together or across a short run, a season is consumed as one object rather than as a habit maintained over months.
That favours tight construction. Episodes written to hold a weekly audience across a long gap do different work from episodes watched back to back.
Material that once padded a long order now reads as slack, so it is cut before it is written.
The trade-off shows up between seasons
Fewer episodes shot at higher intensity lengthens the gap before the next season, because preparation and post-production do not shrink in proportion.
Audiences therefore wait longer and receive less, which makes each return harder to build interest around.
Some productions respond by shooting consecutive seasons together, which restores continuity of crew and cast at the cost of committing before anyone has seen the first one.