When I started at CHUM Toronto in February of 1965 as a board operator/producer, almost half of the ads were 'live reads' by the DJ on air. When I moved into production in 1967, management decreed a change to record these former live reads, and by the early '70s, almost ALL the commercials were recorded, including live tags.

I don't know how you can prove that ads read by hosts or the product's owner can be more influential.
Especially the latter since most of the time when an owner reads their own ads they are horrible.
Take Tom's place.
Horrible.
Also when ads are read by hosts they often are too long.
Those Frank Leo ads are interminable.
Who cares that Joe and Jane were retiring and moving up north and needed to sell their home, but they liked the colour red and their house was red so they had difficulty selling it so they called Frank Leo, etc etc... meantime five minutes has gone by with the audience ( at leasdt me) bored to tears or changing the station.
By the way if Frank Leo's marketing system is so miraculous why isn't everyone doing it?
It's like those miracle natural cures, if they really worked the whole bloody world would be rushing to buy them and doctors would lose most of their patients.
Oh wait, that's because they don't work.