I worked from home 100% for over 4 years. I got a lot done, and surely even outperformed many on-site people. Even got top achiever over on-site people one year.
That being said, returning to office has forced my output to probably triple over WFH years.
My job can easily be done remotely, but being in office introduces almost daily instances where I get pulled in to solve issues outside my normal day to day "expected" duties.
I already knew I wasn't going above and beyond most years at home, I was doing just enough so my boss never even had to watch my work output.
Being on-site my boss now questions if I'm going to burn out from everything I'm always getting pulled into/voluntarily taking on.
The looming layoff threat is surely an additional motivator over "quiet quitting" years, but Elon was speaking facts about WFH just not being the same.
**I'm sure there's some who have a role where they stare at a screen all day and feel it makes zero difference to RTO, but you would really have to be working in a silo if you haven't taken on any extra work with RTO.