From the perspective of epistemology, is there absolute truth in marketing?
It depends on the type of the company and on what aspect they are marketing. No company wants to market their defects, may be negative aspects are not made public.
The scope doesn't matter.
They sell you ideas, your secret desires...
Marketing does everything to sell.
Even if you don't pay for it. For example, the sponsor pays.
Yes, there are. For example, if we are talking about advertising, we could say that "the opinion of the audience (public/customers/potential customers) is paramount." Therefore, the theory must be dismantled and changed if it goes against the marketing research results of the public. Therefore, public opinion has the final word, and not marketing theories or models - those are fluid.