The problem is Arthur Brooks is looking at Trumpism as if it was an isolated bad presidency that led to the upheaval. Trumpism is more akin to the cataclysmic events in our history. After the Civil War the GOP won 9 of the next 11 presidential elections. After the onset of the Great Depression Dems won 7 of 9. Following the fracture of what historians call the Democratic-Republican Party in 1924 (marking the beginning of the robust two-party system Brooks looks to for solace) the Dems won 6 of 8.
It's foolish to look at the 1970s, when liberalism was losing intellectual momentum and conservatism was stretching its legs as a data point for the resilience of today's GOP. If anything those roles are reversed. Progressive ideas abound, and are, for the first time in a while, a decent threat to take control of the Democratic Party.
I would argue, that, If your looking for parallels, Biden is the Dems Nixon, who with conservative support, though wasn't conservative. Conservative activists saw the disaster in '64 as reason enough to get in line with the GOP in '68 and hope to continue to work within the party apparatus to capture it ideologically. One could easily see that dynamic play out over the next decade or so as boomers give way to millennials as the dominant electoral block.
In short, I agree. If GOP activists want to prevent long-term electoral carnage, they need to work with their donors to isolate Trump as a political force. There's no guarantee that any strategy along those lines would be successful, but if there is any path to parity with Dems in the near-term it includes total disavowal of Trumpism.