No, they lower the targets because the evidence of better outcomes at those numbers becomes clearer over time. There are massive, government funded, 40 year+ ongoing studies following tens of millions of patients through their lives to see what happens at different BP levels over the very long term.
There are way too many eyes on the freely available data, and resulting guidelines for some unscientific, ulterior motive conspiracy to go unnoticed. Literally millions of doctors and scientists worldwide.
Almost all BP meds are ultra cheap generics. There's not enough profit in 5¢ pills to fund the bribes it would take.
And in forums where primary care doctors don't think the public is watching, they BITCH and COMPLAIN about the extra workload tighter guidelines put on them, ie "I don't have enough time in the day as it is to manage all these new prescriptions!"
Which shows where their priorities are...