In the UK currently, the A6600 plus kit lens is £1700. The A7iii, plus kit lens, is currently available for is £1900. But it has only come down to that level because it's relatively old. The S5 is being debuted at £2000 including kit lens. I'm including one lens here because I suspect people stepping up to FF from M43/APS-C will largely be starting again, glass-wise. Sony's FF lens compatibility with its APS-C line might give it a modest starting advantage here.
Remember, Sony still has the upcoming A7C to squeeze in to the picture. Common sense dictates that that there will have to be some clear blue water between that and the A6600. The same principle will apply to the A7iv, which I confidently predict will put it much closer to the R6 in price than the S5. As for the R6 itself, I don't know how you think a camera which stops working so frequently 'crushes' one which just works, albeit you have to take more care with focusing issues.