I'm pretty sure that Trump is stronger than polls indicate. I recall the "Bradly effect," from decades ago, when those polled, told pollsters what they wanted to hear.
In this case, many don't readily admit supporting Trump. I spoke last night, with a friend that surprised me a lot.
He is a retired public school teacher. Over 70, still working hard on his investment properties, alongside skilled craftsmen.
The kind of workers, that have been displaced by illegal immigrants.
He surprised me by clearly stating he supported Trump. I had previously pinned him as a moderate-liberal fellow. He was bitching about taxes, about Jerry Brown, about the state of the state of California etc.
The other guy in the conversation is a 50ish Latino business guy. He too is riled up. And he admitted support for Trump.
It is not enough for Trump to carry California in 2020.