Actually, bass did not come here with the Californians. They've pretty much been here for over 100 years. Here's a quote from the WDFW web page on warmwater species:

By 1900, warmwater species were common in many of the lowland lakes of the state. Because of their tremendous reproductive potential, they were soon providing anglers with a wider choice of fishing opportunity in nearly all parts of the Northwest. A survey completed in 1986 estimated that more than half of Washington's licensed anglers fished for warmwater species. Warmwater angling accounted for an estimated 3.48 million days of recreation, or nearly a quarter of the total number of days fished for all game species combined. The amount of recreation provided by warmwater species in 1986 was second only to trout fishing in lowland lakes, and ahead of steelhead and salmon angling.

And note that this survey was done nearly 20 years ago. I'm sure more people fish for warmwater fish now. Possibly more than fish for trout. IMHO, most people will fish for whatever is biting. If the trout aren't biting but there's other fish biting, then that's what they'll fish for.

And I still think it's a waste of money to plant 2.6 million trout, some of which go into lakes that have almost no access to people without boats, and many of which get snarfed up by non-human predators.