I'm not so sure that's the only reason to intentionally distance from the "SmallTalk" brand. There might be a advertising benefit, too, since ST is sometimes maligned for having "lost".
Even without active malignment, Smalltalk is largely perceived as a historical curiosity of primarily academic interest. Even among many people who like it.
Since Pharo wants to position itself as a modern, industrial programming language, it makes sense that the project would want to distance itself from that reputation.
But if you look at the hero myth is the wrong strategy. It's like the immature hero that wants to hide who his father is because is ashamed for some immature reason hence demonstrating that is not ready yet for the challenge of the world. The alternative is, embrace his history, have a clear own identity, and yet come back and rescue his father (not the project but the spirit) "from the belly of the beast" and improve itself and the world by doing so. Not doing it like that will not fit the psychological archetypes of the good stories that marketing needs and fail and waste a lot of effort having at the end of the day to always admit it is a Smalltalk. Not all products can aspire to be legends. This is one that can do it.
"A position (or statement of position) is a cold-hearted, no-nonsense statement of how you are perceived in the minds of prospects. It is your position."