I think people fundamentally misunderstand what the LibDems stand for. There's this perception that they're a centre left party. They are not (and, in fact, I seem to recall Nick Clegg, explicitly saying this when they announced their coalition with the Tories in 2010)
Agree with all of this.
People who like Labour policies but don’t want to vote Labour for whatever reason (dislike of the leader, misconceptions about “Marxism”, just general unwillingness to identify with the left) vote Lib Dem hoping for Labour-lite. Sadly they are actually yellow Tories.
Lots of Labour policies are super-popular with voters. More money for NHS, rail renationalisarion, better public services, taxing the super-rich etc all poll very well until you tell people they are Labour policies. At which point they back off.
Sadly the Tories and Lib Dems are never going to bring in any left of centre policies - they simply don’t believe in them. A new, truly left of centre party would clean up. I’m not happy about that, I’m a Labour Party member significantly further to the left than that, but I do recognise it’s true.