Is there an on-line advertising duopoly?

Remember that complaint?  Funny how it typically came from people who also hated on-line ads (and thus presumably should have wished them to be more expensive?).  Here is the latest (FT):

Meta and Alphabet have lost their dominance over the digital advertising market they have ruled for years, as the duopoly is hit by fast-growing competition from rivals Amazon, TikTok, Microsoft and Apple.

The share of US ad revenues held by Facebook’s parent Meta and Google owner Alphabet is projected to fall by 2.5 percentage points to 48.4 per cent this year, the first time the two groups will not hold a majority share of the market since 2014, according to research group Insider Intelligence.

This will mark the fifth consecutive annual decline for the duopoly, whose share of the market has fallen from a peak of 54.7 per cent in 2017 and is forecast to decline to 43.9 per cent by 2024. Worldwide, Meta and Alphabet’s share declined 1 percentage point to 49.5 per cent this year.

The whole Tim Wu, anti-Facebook crowd has pretty much been wrong about everything from my vantage point…