If you have concessionary bus pass and don’t use it, it costs nothing. The local authority refunds the bus operators for the number of journeys made and central government refunds local authorities.
Concessionary passes provide an income for bus operators on daytime services that might otherwise generate little income and be cut altogether - which ends up serving nobody.
I wrote upthread about the economics of concessionary bus passes. Passes encourage people to travel into towns and cities and spend: cafés, markets and shops, cinema tickets etc, putting money into the economy that might otherwise not be spent and increasing tax yield.
There is a strong argument too for government spending to promote social welfare for people who might otherwise be isolated and lonely. This is one of them.
Providing bus passes also reduces car use which is another good thing - less wear on roads, less pollution, fewer cars vying for precious car parking spaces.
The millionaire argument always comes up as it does with the Winter Fuel Payment. Chances are someone super wealthy isn’t going to be travelling on a bus. (For all we know they might not have bothered to claim their State Pension so the WFP argument becomes redudant anyway.)
Older millionaires are often only paper millionaires with the wealth concentrated in the value of the home. You can’t pay a bus fare with a brick any more than you can pay a heating bill with a brick.
The average income of a single pensioner after housing costs is considerably less than a working person even on one on minimum wage.
I see universal benefits for pensioners as a reward for the poor State Pension after a lifetime of work. There are three million women who had to wait up to six years longer to get their SP and with that their bus pass and WFP.
The issue of travel costs for workers came up in another recent discussion about the rise in the capped single fare. Season tickets make bus travel considerably cheaper for regular users.
There are a number of schemes to help jobseekers with travel costs.