Formula 1's pursuit of a new manufacturer brought a few names to the table. Aston Martin seemed particularly keen. Cosworth has a long history in grand prix racing and joined discussions over the 2021 engine rules.
As it often does, F1 then began to tie itself in knots. Existing manufacturers did not want to simplify the engines and give themselves more work to do if it was not going to entice a new competitor.
Prospective new manufacturers were not prepared to commit because F1 looked like it was not going to simplify the engines. Slowly, the interest of each potential addition to the F1 grid was suffocated. There was no interest more serious - or, perhaps more accurately, at a more advanced stage - than Porsche's.