The term gerrymandering, let alone the practice, goes back to 1812. No one alive lived in a time that it didn't exist or has even met anyone who did. It's an unsavory practice, but it's not some new thing contributing to the decline of trust in institutions.
The last 20 or 30 years (i.e., the last 2 or 3 redistrictings) have seen the use of increasing amounts of data and computation to produce more accurately and more optimally gerrymandered districts. It's fundamentally the same practice that goes back to 1812, but the details actually matter in a quantitative sense.
That's assuming the scope and effects of gerrymandering, and that the public understanding of gerrymandering, remained constant, which is a big assumption.
Yes; It's not uncommon for the gubernatorial race to be highly competitive in a state where one party has a solid lock on the state legislature, for example.
