I think it’s more likely Harvard does away with the traditional letter system altogether. Aside from the fact Harvard operated just fine without it for the first 2-3 centuries it operated, let’s take a step back and try to remember what the grades were to track in the first place: students’ absorption of the material (i.e. “learning”). This type of grade system is better for measuring things that have right/wrong answers— math, memorization of dates, anything mechanical, etc. Yet with calculators and the internet making things like historical timelines and formulas etc accessible even to payment, graders’ job of even grading these “objective” becomes more subjective— if you arrive to the wrong math question, but did all the right high level steps and made a small but cascading error in the beginning, I’d posit that student likely knows the material well and would avoid that error were it pointed out. But from a grading perspective, what is that? 7/10? Same situation to a history student laying out the historical context leading up to some event and mixing up some dates. Things get even more muddled when it comes to humanities.
In fact, off the top of my head, Pomona College and Brown University, both well-regarded schools within academia (and Pomona with I believe the highest undergrad acceptance rate into Harvard grad programs), have the option for every class to be taken as Pass/Fail, except when it comes to later-stage major requirements. Graduation accolades are awarded by professor recommendation, which fosters getting to know your professors out of the classroom better than grades. Anything that needs to be GPA-gated could instead be (likely better) gated by a placement test.
Knowledge is not a 0 sum game. Maybe instead of trying to adapt our current education circumstances to to an old grading system, it’s time to think of a new system altogether.