That second photo is much more helpful - thanks!
My understanding is that these funds are forced to pay licensing fees to Standard & Poors (S&P) for tracking the S&P 500 index. Removing that requirement frees up the fund to stop paying that licensing fee. The downside being the fund is being trusted to do it's own index, which is riskier than following a third party index.
I suspect it's motivated by the amount of churn in the S&P 500 recently. As companies lost significant market cap, a number (I only recall Macy's, because I own shares) of stocks dropped from the S&P 500. They became small cap stocks, showing another advantage of owing a total stock market fund.
Somewhere between S&P 500 churn, the license fee, and having a significant number of people who trust Fidelity, I think they're going to try making their own index to track. It's less transparent, but I would trust them to follow something resembling the S&P 500 even after it's no longer a fundamental policy. Fundamental policies can only be changed by a vote.