[Edit: I am not saying that Juneteeth won't get special treatment. See my nested commented in this thread.]
State governments may or may not recognize a given federal public holiday.
The only exception to this would be companies (and schools) that will use Juneteenth as an education day instead of giving the day off. (I hope companies don't do that. If I want to get educated I have books and the Internet)
True, though Juneteenth may be different here. It could be considered the most basic signal of whether a company cares about Diversity & Inclusion. Of course this itself would be meaningless, but perhaps eventually the lack of this holiday may say something about that employer.
P.S.: The big tech company I work for has more federal holidays off, but Columbus Day and Veterans Day are not among them.
So, please consider me a data point of 1 which does not fit your paradigm.
Corner stores and restaurants don’t close.
So one way companies will not give any more time off is by just saying "feel free to use one of your floating holidays on Juneteenth".