10x seems like an exaggeration.
I've googled the hell out of this question (NQ vs ES) and the preferences I find from other players seems to balance out fairly evenly with some preferring either for various reasons.
I also did my own preliminary research and have done some testing:
Which markets or instruments are you trading?
I think my own test-trading coincided with a period where NQ greatly outperformed ES with very strong one-way momentum moves, but I don't think this holds true long term.
Sure, overall, it does offer considerably more bang for the buck, but I find that just like ES it seems to also get stuck in ranges where it's very noisy and with plenty of back-filling/retraces. I tend to find that ES behaves a bit more predictably and orderly where NQ in comparison may overshoot a bit and be more loose. On average, NQ probably offers better R/R ratios and more opportunities on any given day, though.
With the current volatility, I'm happy to stay with ES as that's what I know, but if volatility should completely contract at one point, I'm sure it would be necessary to migrate to NQ then.