Gerrymandering can keep a relatively unpopular party in power for longer than it otherwise would be. Assuming the unpopular party becomes even more unpopular, just how unpopular would they need to be before the stratagem of gerrymandering itself is insufficient to support them?
For example, in 2016 gerrymandering enabled Republican candidates who received 50% of the popular vote to win 9 out of 12 available Congressional seats in North Carolina. That is, half the votes, but 3/4 of the seats and power. And suppose that as long as they hold 3/4 of the power, they'll continue to gerrymander.
Now suppose in the future, the Republicans become more unpopular, and receive only 25% or 10% or even 1% of the North Carolina vote, can gerrymandering alone sustain their hold on the majority of seats, or is there some necessary numeric limit that would eventually be reached?
Note: for the purposes of this question, please ignore other concomitant stratagems by which unpopular parties might squeak by, and also suppose there are only two parties contending. For US voting systems Reynolds v. Sims, 377 U.S. 533 (1964) et al would apply, so that the gerrymandered districts must have approximately equal populations.