We’ll never win over Hispanics and Asians so long as mass immigration continues. If we cut off mass immigration like we did in the 1920s, then over time they might start going our way in significant numbers, but as long as the gates are open it’s not going to happen. It’ll only get worse.
Unless of course the GOP moves left, and not just on immigration, but on a lot of other things too.
We used to do fine with the asian vote as recently as 12 years ago. It used to be a Republican leaning voting block. Now it is voting Democrat at an even higher rate than Hispanics. Democrats reach out to these voters, they've learned how to talk to them - and what not to say to avoid alienating them. We need to do a much better job of this.
Cutting off immigration is not going to happen. The Democrats will never allow that because they know we are importing more Democrat voters. We either learn how to reach these people and get them to vote for us, or the demographic problem is only going to accelerate. We really aren't going to be able to even win Texas in 10-20 years or less.