The right has moved far more than the left. Just looking at today's news, we find a prominent right-wing activist was convicted of plotting to overthrow the government: https://www.bbc.com/news/world-us-canada-63802649
The only area I think you could unequivocally say the US left has progressed on is civil rights for LGBT+ people. But in terms of things like labor rights, a social safety net, environmental conservation, gun control, election integrity, and business regulation, I'd say the center of the US left hasn't moved much in decades, much to the frustration of the more activist portion of the left. Note that people from other countries often see the Democratic Party as a center-right party.
Further, I think the Pew stuff is flawed in a number of ways. One, it comes after the Reagan era, missing a time DW-NOMINATE shows as important to right-wing polarization. Two, it doesn't include the Trump era, when polarization hugely spiked. Third, and most important, 9 out of the 10 questions are not suited for directly measuring ideology. The one I think is actually a decent measure of ideology is "Homosexuality should be discouraged by society" vs "Homosexuality should be accepted by society". The rest of them are practical questions relative to the circumstances of the day. E.g., "The government today can't afford to do much more to help the needy" is a question that's explicitly about the current state of the budget. If the budget improves, then more people should answer that as yes regardless of ideology.
The measure I'd rather see is the extent of ideological litmus tests for access to power. E.g., look at the way the right's orthodoxy on abortion has hardened over the years. In the 1970s it was possible to be a pro-choice Republican and a pro-choice evangelical Christian. Now neither is acceptable, so much so that the most prominent Republican pro-choice group just gave up a few years back: https://www.nytimes.com/2018/06/24/opinion/abortion-rights-r...
Or you could look at the way large portions of the Republican party have polarized around things that are provably false, like that Trump won the 2020 election, that January 6th was a left-wing false flag, or that ivermetcin is a good way to treat covid. That is wildly asymmetrical polarization, and it drove litmus tests for Republican candidates across the country. Nothing similar exists on the left.
Furthermore, there's only 535 members of Congress, out of 300+ million Americans. DW-NOMINATE only examines a very very narrow segment of the population.
By comparison, the Pew survey was based on directly asking people their positions on various issues and measuring political uniformity. This didn't involve the highly subjective task of drawing regions on a chart and deciding these people are center left, these people are far left, etc. Instead it examined how likely people were to have uniform versus heterodox views. It also didn't exclusively study on politicians, it used representative sampling of the general population.
1. https://en.wikipedia.org/wiki/NOMINATE_(scaling_method)#/med...
And 1/2 of the US has ideas that do not match the current left.
I've always been a classical liberal: https://en.wikipedia.org/wiki/Classical_liberalism
These values are unthinkable for progressives today.