You have it right. Whether the source of money is media tycoons or candidates, Pollsters are in the business of keeping their source of money happy and getting repeat business.
The same is true of paid political consultants. Their #1 skill is raising money for the campaign, which means for themselves. Examples: Shrum and Murphy can raise money even though they always lose.
The pollster who seeks the truth is rare, but might exist.
The paid political consultant whose #1 priority is his candidate winning is rare, but might exist.
They exist. Campaign management may not release their results even to the campaign staff, but they have to know the truth. That's most of what I did for a living, and I always reported accurate results to the best of my ability. I included the uncertainties, not just the classic statistical uncertainty but also in my assumptions.