Yes, this is a very tempting argument & quite convincing.
On the other hand, is this not a rehash of the Nifty 50 argument, which worked... eventually, if you waited 30-40 years from the peak? And particularly when it feels like an increasingly consensus view?
On the other hand again, even if they do turn out like the Nifty 50, the top might be 5-10 years away, and they'll carry on (& may grow more into their valuations with new technological additions to their arsenal).
I know you're flexible, so are your MGK Puts in case they turn out not to be bond subs?
Anyway, I fear that I have my own bias to deal with as I'm woefully underweight these ultras, apart from the tiniest amount I bought at the bottom last year, before I lost my nerve. So I'm struggling to buy more at a much higher price.