Honestly I think this is a good way to create more competition in the advertising space which is currently dominated by Google and Facebook.
At some point some “smart” executives are going to decide it’s better to cooperate rather than compete… that’s when consumers get exploited. Which is why the threat of regulation is important.
I don't think it's a good thing that another trillion dollar company is trying to get a share of the advertising business. It would be much better if we had more small and focused companies.
Their sources of profit are from very different products and services though.
Microsoft and Alphabet and Amazon have cloud computing.
Alphabet and Meta earn money from ads.
Apple is the only one making money on selling hardware.
Microsoft sells software, with the bedrock being Excel.
Amazon is selling logistics, physically via warehousing and delivery and virtually via a website others can sell on.
MS is selling Surface. Google is selling Pixel. They aren't necessarily successful but they are trying. The only outlier is Facebook which doesn't try to sell hardware or services.