Consider this passage (Source):
Few question the propriety of the current haste on the part of manufacturers to bring out "new and improved" products at the prevalent rate. At one time, in the dim, distant past before the advent of television, it was the vogue for products to be advertised on the merits of their "tried and true" qualities. Few advertisers were impious enough to jettison any part of a product that had been accepted by the public. Year after year, the local grocer store owner would proffer the same box of cereal, the same house cleaner. The acceptance was of the time-tested product, and it appeared almost unconscionable for the manufacturer to change his merchandise.
Q1: I cannot figure out the process of advertisement in that era. Does it mean there were some semi-shopes whose job was to check quality of the products and their staff monitored a product over a fair amount of time. After that, store owners would obey the instructions and recommendations made by those semi-shopes which they were not necessarily sincere?
Q2: What does "The acceptance was of the time-tested product" mean? does one which was more tested, it has a better chance to be a successful product? If so, why the author didn't say:"The acceptance was for the time-tested product"