We'll have to see if they end up putting ads in the existing paid service tiers.
Why is the profitable company chasing the business practices of the companies that are burning billions of dollars per year?
Peacock was an example of how a large group of people prefer ads to paying, which means it wasn't worse for them. This was in the context of my comment of Netflix potentially adding a "free" ad supported tier, which could make the content available to those people who couldn't/wouldn't pay.
But, as you point out, them not being profitable suggests that "free" with ads isn't sustainable, meaning a Netflix "free" tier probably wouldn't work either, assuming they were similar to the 15 minutes/hour of ads that Peacock has.