The primary market for the Prius is Japan, so they build every car there. The Prius competes with the Corolla and the Camry. With declining sales, it doesn’t make sense to expand production to the U.S.
Only the more common hybrid models are assembled in the U.S.
PHEV and electric vehicles are assembled in Japan.
Corolla Cross hybrid in assembled in the U.S. but the Corolla hybrid is made in Japan.
American vehicles were locked out of European countries for decades due to the high tariffs imposed.
I am finding the Corolla hybrid production has been moved from Japan to Blue Springs, Mississippi.
Maybe so.
It might also have to do with a combination of reliability years ago, or a mismatch between the cars America was building vs what the European market desired.
Case in point: Toyota’s ‘Innova’ is one of their top 3 selling models in the Philippines, but the combination of its particular size, design, and features means it would never sell as well as models like the RAV4 and Sienna in North America.
There’s a clear lack of understanding of the cost of Relocating or Building a vehicle Production Line.
Low volume 10,000 to 50,000 units per year $50 million -$200,000 million.
High volume 100,000 units per year - $500,000 - over a Billion
So if you are the President of GM, threatened with a 50% Tariff that may only last for 2 years, and facing these enormous costs and potential relocation production delays what would you do today?
Commit to relocation? Do nothing? Head to the roulette tables at Vegas? 
There are two GM light truck factories in the U.S. Are they operating at capacity? Is there a need for an additional factory?
GM already increased light truck production at Fort Wayne Assembly by 20% in response to the tariffs that might or might not happen. It appears that light truck production was not decreased in Canada.
From the above GM Authority link…
“GM has revised its guidance but does not plan to move EV production to the U.S. from Mexico. The new guidance sees EBIT (earnings before interest and taxes) being in the range of $10 billion to $12.5 billion in 2025, rather than the previously forecast $13.7 billion to $15.7 billion, to take into account the aforementioned $4 billion to $5 billion in tariff exposure.”
To be clear, that’s a DECREASE in the Projected Gross Profit of $3.7 Billion ($10-$13.7) on the low side or $3.2 ($15.7-$12.5) Billion on the high side due to tariff exposure.
Whether you’re GM or a Small Business Owner or Wage Earner, a projected 20% decrease in income is a Big Hit and no matter how much Mary Bara tries to “perfume the pig” or “wave the Flag” it’s still a Big Hit.