I've been voting for almost 40 years. Democrats have been running on that platform basically the whole time. Quite frankly, it is how things work. Dems are absolutely leaving votes on the table by running bad platforms. Mamdani is running a very different platform and is absolutely crushing it out there.
And I think the fact that the party is losing more and more often is a clear indication the lack of votes for it are having an impact, and are resulting in new candidates coming forward to capture them.
Obama ran on a platform which he didn't ultimately move forward on once elected, but at least he had a vision that moved people.