This is hardly the only issue the right is winning the argument on in the US. The Democrats are struggling including among those people they see as their solid base voters. The working class no longer trust them or see them as standing up for them economically, the Hispanic population is well on it's way to being a Republican voting block, and even the black population seems to be increasingly less loyal.
Identity politics, the kind of approach that is making so many American cities war zones, an inability to talk about immigration rationally, an authoritarian streak that doesn't sit well with most Americans - all of these are turning people away.
From a slightly more cultural angle, over the past 5 years, something I've noticed is that if you look at political writing, public intellectual types, it seems like at this moment in time, the right is producing more really interesting, intelligent writing and ideas. There are some very good writers and thinkers contributing to the political discourse, or older ones who are being discovered. There is a huge phenomena at the moment on youtube of young black Americans discovering Thomas Sowell, for example. Douglas Murray is another example of a person on the right producing some pretty solid stuff that is also accessible to the general public. There doesn't seem to be a comparable amount of good writing, or interesting political thinking coming from the left at the moment - a lot of it seems pretty stale.
To some extent I think this may be a kind of natural cycle. But if the left wants to get in on it, they need to start engaging, which they won't. So the kind of attitude that says, how do we stop the right from capitalizing on this so we can get back to left as usual politics, is part of the problem. Talking to people on the right as if they might have a point, and taking their arguments seriously, does not contaminate you. If you won't engage with the questions people are concerned about, you will inevitably produce shit and will lose their interest.