The article explains why eBay shouldn't advertise against the term "eBay", all very logical. ... Until a competitor starts advertising against the the term "eBay". At which point, online advertising becomes protection money.
Click-through rates will be very low. In most countries you cannot impersonate another company, so they cannot call themselves „eBay“ in the ad copy.
Furthermore, Google will "dynamically" assemble an advert based on the current search to 'optimise' click-though (and they recently sent a mail out making it clear this will be the only type of text ad going forward)
They think they're optimising "click through" rate.
But what they're really doing is using heuristics to find the advert that's most likely to be confused with the top search result.
Either way, the ad platform wins.
And companies pay their protection money.