A very easy way to break this argument is to not look at huge known companies like eBay and Amazon, but brand new companies 1-2 years old that have grown almost entirely by online ads. Eventually word of mouth kicks in, but there are plenty of smart operators that built their entire brand and revenue off of ads. Works best in online direct to consumer brands.
Now big company marketers are used to thinking of US as a homogeneous market for efficiency reasons and so TV still works in US if your target audience claims a broad demographic. However, they're beginning to learn that you'll simply not reach enough consumers if your target demographic is say young adults in the West coast if you do a TV heavy plan. US in general lags China in media landscape shift but the media behavior of the more valuable demographics are actually much closer to China than averages tell you.