I think there are a few factors in play - for some, home working doesn’t suit at all. For me, I can do it, but don’t like doing it for more than the odd day here and there and find getting on a lot easier in the office much of the time.
Indeed, and I expect that you would not be alone in that regard.
I've heard of one company who was totally WFH during Lockdown who have opened up their offices for the circa 30% of their staff who would like to work in the office.
There's many reasons, homes with no space to work, people who live alone and their primary weekly social interactions are at work, those who house share and need some time away from their housemate(s), and so on.
It's one of the reasons that the death of the railways is likely to be greatly exaggerated.
Whilst 50% of the railways business is commuting and 40% of all work could be done at home (20% of total), by the time you allow for 20% of people choosing to work in the office and for 40% of working days to be office related (even those 100% WFH actual would end up needing to be in 5% of the time, 12 days a year). Meaning the maximum fall would likely be around 10-15%.
That would likely mean a return to 2015, maybe as far back as 2013, passenger numbers.
It would also be likely that it would impact London more, especially those metro lines within the M25.
However given that some peak services into London are running at 150% of capacity a reduction of 40% would mean that there would be 10% of seats free, making travel a lot nicer and therefore attracting people who previously wouldn't do it because it was so overcrowded.
The other thing to bear in mind is that you may get some crazy long commutes happing for those who primarily WFH. I know of someone who works for a US firm (did so from pre Covid-19) who "commutes" to the States a few times a year for a week at a time.
If that's possible then why not live in Truro rather than Twickenham, Bournemouth rather than Basildon, Ipswich rather than Islington, Peak District rather than Peckham?
I suspect that a lot of second homes may well suddenly become main homes and then have a London flat for when you and/or your family visit.
With a mixed use block you could even have the ability to commute to work the days you're in the office by using a lift!
I could certainly see some companies looking into having corporate lodgings within their office space with them being able to be booked much like meeting rooms are. Depending on your grade depends on what allowance you are given, although I'm aware of one company which gives staff a set number of employee points which they can use for what they like (more holiday, company car, more pension contributions, etc.) and so use of lodgings could be added to that list.
Chances are they would be fairly basic, maybe even just a private bedroom with shared wash facilities (using those available to all staff).
However such a setup could result in less weekend ghost towns in certain areas of towns and cities as there would be people around in those areas dominated by offices and could go some way to reverse the losses of those places which exist to serve the office workers. In that there would be more custom for them from those staying in their offices, with breakfast and dinner likely to be needed to be brought rather than prepared.
Whilst such sleeping spaces would require extra floor space, this would likely be just floor space which was previously needed to provide desk space for your staff and is now surplus as there's a greater level of WFH.
If expect that it would be fairly basic, a small 2m X 2m box with a bed some draws and a hanging rail. No need for a TV (as people would just use their own devices, although one with the ability to cast the content from your device to it could be provided - so Apple TV/Chromecast) nor a need for a desk (as they could just use one of the office ones).