Policies were popular in isolation when you didn’t know who was going to deliver them. Taken as a package they were a wish list of stuff people had no faith in us to deliver that didn’t speak to their priorities.
I’m a Labour activist and I couldn’t tell you our headline health policy other than “Tories bad”. That’s an issue we are strong on which a significant portion of the electorate count as a top issue, and we couldn’t get a message across. Same for the environment outside of buzz words like “green industrial revolution”, it means nothing to the average voter.
We had nothing to say on Brexit, crime, immigration or really the economy despite those being the other top issues.
We need to talk on voters terms, not ours, and have the humility to accept where we need to compromise with the electorate.