Since Cambridge Analytica, Facebook has accumulated blunders and yet it makes every effort to redeem itself an image by wanting to reassure on personal data and trying to become more "transparent". But since early August, the mention "It's free and it will always be" has been replaced by "It's fast and easy" while the latter had been in place for more than a decade. Even if the registration and use of Facebook are free, the American firm uses our data and an aggressive advertising system to make money because personal data is worth a lot.
We can assume that Facebook is working on a Premium offer, especially since in the Platform Policy we read in article 7 clause 11:
We do not guarantee that the Platform remains free.
We could get closer to what Google offers for YouTube, a subscription to 12 euros per month called YouTube Premium that allows you to watch ad-free videos, download them for offline reading, and access music offers YouTube Music Premium and Google Play Music.
If not more simply, the social network no longer wants to use the mention, because the European Parliament decreed last May that the use and exchange of data was a means of payment. By suppressing it, it would cut the grass under the feet of its detractors.