It is commuter traffic that is unsustainable - huge investments in rolling stock and infrastructure that even before the pandemic was required just for a few hours mid-week carrying people at discounted rates. The growth in public transport use in recent years has been exactly leisure traffic providing decent loads on some routes throughout the day. As Peter Hendy has made clear the future is a railway serving the leisure market.
The teenagers and children using the railway today are the full fare paying passengers of the future and should be encouraged not demonised. Its good that public transport is for everyone and not just for middle class middle aged men in suit.
I'm not demonising it, just making the point that this market doesn't really cover its costs. The teenagers and children won't be filling weekday trains with leisure trips this time next month because they'll be at school, and this year's leisure boom will likewise tail off from September onwards as (1) fewer people are on leave, (2) people return to the workplace, (3) pent-up demand easer, and (4) weather tails off and days get shorter. Then what are we left with?
Planning a recovery based on leisure is very risky because of so many factors, not least the discretionary nature of leisure journeys. They're very sensitive to a range of factors, not least price - jack the price up too much and the journey won't happen, which is not good news for an industry which needs to cover costs.
At the moment I'd be looking to get back those commuters who *are* currently travelling to/from a workplace but are using other means, specifically the car. The way to do that is to offer them reliability, space and comfort. Max out train lengths (which the London & South East area fortunately has the infrastructure to do), reduce the number of services running in order to trim staff costs, and try and sort the current issues with reliability.