Obama was by far the best US president in recent history and maybe ever. Then the Dems just went like OK we'll never ever do something like that again.
Here's what I told someone else:
The Dems lost the house of representatives in Obama's years 3 and 4. Again in years 5 and 6. And then lost both the house of representatives and the Senate in Obama's years 7 and 8.
You need more than just the president. They lost in 3 out of 4 of Obama's cycles. And you're wondering why they aren't running to the left? They lost 3 out of 4.