Nope. They had a platform. Even more of a platform than Trump (granted, that was a low bar).
Yes, they had a platform, but they still took certain voting blocs for granted and lost those voting blocs as a result. They relied on "we're not Trump" to continue having those voting blocs keep voting for them. Meanwhile, Trump went to those voting blocs, sold them a pack of lies, and got their vote even if he's not going to do anything he said he was going to do.
This is not what happened at all, even remotely. There was a campaign, it a had a platform, there were policy details. But Trump got a lot of attention from the media, and rightly from the campaign as well.
Yes, there was a campaign, but a large portion of that campaign was "we're not Trump." In Michigan, almost all of the ads that were run focused on how bad Trump is without actually spelling out what Harris would do. Even the billboards and things like "I'm a two-time Trump voter and I'm voting for Harris." We had ads like "Trump gets up and looks at his list of enemies, Harris will get up and work for all Americans" and "Harris will welcome Republicans to the table." In addition, parading deeply conservative politicians like Liz Cheney and Trump's former staff so they could say how awful Trump was played into that strategy, too.
I'm sure it varied from state to state, but the main message in Michigan, at least, was "we're not Trump." It's a sound message that should've worked, but people didn't care.
Harris would've had a much easier time had Biden not sought reelection and there had been a primary. You would've heard up and down which each perspective candidate would bring to the table and there would've been way more time to get the message out there. Harris had a little over 3 months to develop a campaign and tell people about it. That's not enough time, which is why I think they relied so heavily on "we're not Trump." That was a straightforward message to put out there.
They did. But people need to have their ears open.
Obviously, they didn't do a good enough job reaching those voters. Yes, it was a limited timeline, but if you wanted to better understand Harris at all, you needed to go and research what she'd done as VP and what she was planning to do as a president. Most voters aren't going to research anything or, if they do, they're going to do the bare minimum to figure out where a candidate stands on their specific pet issue.