That DNA takes a really long time to shed too.... it basically took the Southern Strategy for Democrats to start losing the FDR/New Deal DNA in the south, but even that was a slow burn. The suburbs have become more hostile to the GOP in recent years, but that has also been something that has happened over time.
To put into context, we've internalized a lot how bad suburbs have become for Donald Trump, particularly in the northern United States, but prior to 2008:
Chester County PA (which Biden won 57-41 in 2020) voted once for a Democratic candidate between 1916 and 2008 (Johnson 1964)
Kent County MI (Biden 52-46) voted three times for a Democratic candidate between 1888 and 2008 (1916, 1936, 1964)
Kane and Dupage Counties in IL (Biden 56-42 and 57-41 respectively) NEVER voted for a Democrat in the 20th Century
Trends exist, but often I think people expect stuff to happen overnight and it doesn't because people are conditioned to vote the way they always have. Or that you vote or participate the way everyone always has because that's the way to get ahead wherever you live (which is definitely the case in the county I grew up in).
Either way, it happens in drips and drabs.