The article indicates the opposite:

"The fruit had a larger pit and less flesh than today’s avocados..."

There are two types of avocado that I see. One has a large pig, close to ping pong ball sizes. Then there's another with a much smaller, marble-sized pit.

It does say the fruit has been changed by humans, so presumably there is some evidence supporting that.

>Back when the giant beasts roamed the earth, the avocado would’ve been a large seed with a small fleshy area—less attractive to smaller mammals such as ourselves. Through cultivation, humans have bulked up avocados so there is more flesh for us to eat.

It also mentions that there are still wild varieties around.

Those could still show some effects of cultivation though, it depends on how much information there is too study and so on.

Given it mentions Cenozoic, etc. I assume there is a fossil record. Leaves, wood, seeds - all definitely fossil-worthy.

If it was artificial selection, wouldn't the nut be smaller? All cultured fruit has really small nuts/seeds.

You can only go so fast when it takes 10 to 15 years to see what you got. They also don't breed true, so lots of those plants will produce uninteresting fruits.

Trees like oaks have the potential to be great producers of crops but have largely eluded cultivation, because they take decades to fruit for the first time.

peach pits are pretty big