tl;dr:
... the most problematic shortages will begin to ease in the third or
fourth quarter of 2021, though it could take much of 2022 for the
resulting chips to work their way through the supply chain to products.
The supply relief will not be coming from the big, national investments
in the works right now by South Korea, the United States, and Europe but
from older chip fabs and foundries running processes far from the cutting
edge and on comparatively small silicon wafers.
... Despite the auto industry’s desperation, there’s no great rush to
build new 200-mm fabs. ... More than 40 companies will increase capacity
by more than 750,000 wafers-per-month from the beginning of 2020 to the
end of 2022. The long-term trend to the end of 2024 is for a 17 percent
increase in capacity for 200-mm facilities. Spending on equipment for
these fabs is set to rise to $4.6 billion in 2021 after crossing the
$3-billion mark in 2020 for the first time in years, SEMI says. But
then spending will drop back to $4 billion in 2022. In comparison,
spending to equip 300-mm fabs is expected to hit $78-billion in 2021.