Well, we do use our oldie ENCTS (English National Concessionary Travel Scheme) bus-passes for travel into the city centre; also to various local shopping centres. Without them, we would rarely visit these places as driving in Birmingham is a nightmare at the best of times and car-parking fees extortionate. Also I tend to use public transport whenever I can for my football matches. But we are in a city with plenty of buses and routes; if we lived in a rural area, these passes would be pretty much next to useless due simply to the lack of bus services.
Certain local authority transport areas who administer the scheme for the Government have added various perks, such as free travel beyond 23:00 to the end of the day's services, or cheaper fares before 09:30 on weekday.. Here in the Centro region, we can also use the tram and trains within the West Midlands for free. Centro have just being reviewing these perks in the light of the cutbacks, but thankfully they are retaining the tram and train travel perk for the next two years. South Yorkshire pass holders are not so lucky as I gather their similar local train travel perk is being withdrawn from April this year.
The annual charge idea (WM's £30) was looked at as an option here in the West Midlands, but wasn't persued. I guess the costs of administration were simply too high.
As I understand it, rightly or wrongly, I think I read somehere (don't quote me as I can't remember the source) that the way they divvi the money up here, the local bus companies receive just 80p per OAP journey. That compares with a £2.10 single fare. So if you made a 25p flat rate charge, who does that 25p go to - the bus companies or the transport authority? Take away the concessionary bus passes and how many old folk are going to want to make regular journeys for a minimum £4-odd round trip? I'd say a very high number of passengers after 09:30 are pass-holders - take them away and many routes would simply become uneconomic.
And as an aside, London Buses will shortly no longer be accepting cash for fares, it will be all smartcard technology in future - which adds another layer of complication on charging cut-rate fares ..... West Midlands and other areas will no doubt be going down this route themselves.