A month ago, I would have been inclined to agree with you, but not now. The AV 10 is significantly improved in so many ways from what I had before.
The big issue, is that the jury is still out. This "surround" technology is now reaching maturity, I believe.
So the issue is not only if the AV 10 gives significant and noticeably increased performance over the AV 7706, which it does, but will it have a significantly longer lifespan. On the later the jury is still out.
However the 7705 lasted five years, and the 7706, three months. A dealer on here says not to expect more than a five year lifespan from these types of units.
So, if the AV 10 lasts 20 or even 10 years or more, it is the better bargain. Now the answer to that question is obviously not known. But from inspection of my unit, I strongly suspect it may last 20 years or more. So. my view is that the AV 10 may well be the more economical purchase and the better financial bargain by miles. My strong hunch at this time is that is the situation and the best way to regard the purchase. The downside, of that being the case is, that the cost of entry has been significantly increased. Since the 7705 could not be repaired, which is contrary to Federal law by the way, then I am prepared to downgrade the 7705 and by association the 7706 to junk status and very bad value for money.
I think part of the reason for this is the drive to Atmos, which has greatly increased complexity. I think the downgrade in quality is probably related to a futile attempt to keep the purchase price lower. That is never a good idea. I say this as I have a couple of 15 year old Marantz AVPs still working fine, that are 7.1 units.
Sure I was concerned about the cost of the AV 10, which was probably the major factor in purchasing the AV 7706. But that proved a bad decision technically and economically.