Does this mean that these ETFs are now cheaper than VTSAX?
It might. You need a $10,000 minimum to buy VTSAX, after that of course, adding additional money is free.
If VTI was commission free, it would make the barrier to entry lower, and thus lower less expensive.
You can only buy VTSAX at Vanguard, and with a Vanguard account buying VTI is commission free already. All Vanguard ETFs are already commission free, but next month Vanguard will be offering many other ETFs at no cost as well.
I think this means that ITOT, with 0.03% expense ratio and 3451 stocks, becomes a better value than VTI, with 0.04% expense ratio and 3610 stocks.
I like having access to more ETFs at $0/trade, but it's a strange move for Vanguard. John Bogle didn't like ETFs because holders of ETFs tend to buy and sell them more often. And he's probably even less enthusiastic about people doing that for free, which will encourage it. Plus funds like ITOT will cost $0/trade, and being cheaper than VTI, will probably receive more investment dollars going forward.
Maybe VTI will learn to get a bit leaner, and lower it's expense ratio to 0.03%?