To be more and more persuasive?

Dear teachers:

The following is an excerpt from 60 minutes.

Sources: https://www.cbsnews.com/news/brain-hacking-tech-insiders-60-minutes/

Could you please let me know the meaning of "to be more and more persuasive" in this context?

Tristan Harris: No. And I think this is really important. Because there’s a narrative that, “Oh, I guess they’re just doing this like we used to gossip on the phone, but what this misses is that your telephone in the 1970s didn’t have a thousand engineers on the other side of the telephone who were redesigning it to work with other telephones and then updating the way your telephone worked every day to be more and more persuasive. That was not true in the 1970s.

Thanks and best regards,

David Kim