Okay, I am going to go on record in thinking of the possibility that our Delta wave could last longer/look different than in India or the UK.
Reason: With higher vax levels, infections are like trying to light wet firewood. It's harder to get it going; but if you keep tending it and supplying it with some drier kindling, you can eventually get it burning, but not as hot and just slower to happen. India had low vax, so the whole country burned like a summer wildfire. Great Britain is a lot smaller geographical area than India, so despite the presence of wet wood, it was still able to work it's way through the island with regional burns overlapping.
The US is so large, and so patchwork in terms of wet and dry wood, I suspect it's going to act way more sequentially, while India and the UK burned somewhat in parallel. Missouri, Nevada, Florida are going to burn through, but other states aren't going to start burning until those states are done. The same phenomenon we've seen throughout this pandemic. The country, as a whole, will be dealing with things longer, even if the timeline in each region is similar. We're not so much up and down, but up, down part way, plateau, down more. That plateau period will add up to things lasting longer than "we just have to get to September." Come September, I expect the names of the affected states will have changed, but it won't be over.