On gun control there is no conceivable way gun ownership, gun crime and gun death statistics can be meaningfully changed. They are just too many guns out there already. Those states that do have 'strict' gun laws by US standards are right next to ones that don't and have open borders. As has been said many times, once Sandy Hook happened and didn't shift the consensus on the issue, it was all over. Face it, school shootings are going to be a fact for a very long time. You can have some local regulation like no conceal carry and such, fine, but banning guns and getting them off the streets and out of people's homes at a society level is impossible and pretending that it isn't is disingenuous.
On abortion, pregnant women are just going to go somewhere that allows abortion. Face it, women are going to get abortions if they rally want them. You can make it harder and coerce some vulnerable women, but broadly you can't stop them all you can do is mess with them.
The only effect of strict punitive anti-regulation in either case is to aggravate members of the pro-community, and harm people in edge case situations.
At least that's how it looks from the other side of the Atlantic.
I suspect immigration actually has a lot to do with it. I have a theory that, in the long run, immigration prevents the development of a meaningful left-wing party in the U.S. The left of center party ends up getting co-opted by immigrants who are open to same change, but not that much.
You can see this happening in the U.S. in real-time. Eroding support among hispanics may well cost Democrats the election in 2022. A notable fact about Hispanics is that they enjoy strong income mobility--typically moving up from the bottom to the middle within a couple of generations: https://academic.oup.com/qje/article/135/2/711/5687353. If you're vastly better off than your grandfather who came here from Mexico, you may well be skeptical of efforts to change things too much.