Surely the same argument applies to masses of the workforce working from home?
I do a job that can't be done from home so can't comment personally. My friends who are are a bit more split than the opinion on here but here it seems that peoples' lives are much better, seemingly with no drop in quality or quantity of work done whatsoever.
But pre pandemic, this wasn't happening at this scale and there were no serious calls to essentially change how vast tracts of the workforce work.
I would argue my productivity has been higher these last few months, if only because I save the equivalent of a whole day's work from not commuting. But it isn't perfect and there are projects we are parking because we cannot do them remotely. We have also had to work pretty hard trying to maintain the social aspect of work and help with mental health. People are participating in stuff they would ordinarily not, like wellbeing sessions and mindful hours.
So, I think we cannot maintain this level of productivity long-term; we shall have to go back. I just don't think we will work in the office quite as much as before, now that we have seen how much we can do remotely. Hence, the need for offices will be much reduced eventually.
I think Offshoring certain operations is not quite as easy as having remote working. For one, there are gains in being proximate to hubs of companies up and down the value chain that support your operations. Similarly, being near innovative hubs is beneficial: there is a reason why a bunch of tech companies have sprung up near Cambridge, in the so-called Silicon Fen. Whilst the big companies can perhaps set up their own hubs, small and medium size companies (which are the majority) are dependent on others to form a hub.