All of which will probably reduce substantially post-Covid 19. Very significant numbers of past commuters have now appreciated that their work can be completed remotely much of the time. Season ticket sales will plummet and the London peak overcrowding will reduce.
In the short term almost certainly, however there could well be other factors which come into play. For instance in the medium term there could be those who have "just" kept hold of their jobs may be included to look at ensuring that they can cut their costs at the drop of a hat. Which is where rail comes in as you just don't renew your season ticket, whilst cars have longer term costs (lease costs, insurance, etc.) which will still need to be paid if they are not being used.
I think the jury is still out. I think there will be a drop in people commuting all 5 days per week.
But commuting 2-4 days per week (depemding on individual circumstances) will establish itself as the norm...which makes doing a longer commute fewer times per week much more practical...the sort of distances HS2 will be practical for. Fewer season tickets, but more higher-yield daily or carnet-type tickets.
Especially if people can do the journey off-peak in at least one direction and make use of working time on the train. People won't generally want to cut off from face-to-face time in the office entirely. In some industrues, it is pretty much essential to foster the greatest creativity.
The other thing to consider is those households with more than one car, if two people work from home 2 or more days a week then rail may benefit.
As an example if it's 2 days a week at home for each person when their days could be that there's only one day where one car wouldn't be sufficient. As such rail might be used for that one day, however this would also likely result in other occasional rail travel.
Given that 80% of travel is done by road, whilst rail is 10%. As such even big dogs in rail could be offset by small changes in road use.
The other thing to consider is that air travel could well change, which could also benefit rail, especially HS2.
For instance Southampton to Manchester would drop from 4:00 to 2:45, which would potentially make rail a faster option than by air and certainly more frequent.