I think there are a few reasons.
Firstly, if you don't use cash a lot, you're not going to have a lot of coins.
Secondly, if you don't have a lot of cash on you then you need to get money from an ATM. Finding an ATM that issues fivers is not easy. If the smallest note usually available is a tenner it causes issues.
Thirdly, bus companies don't advertise their fares so it's hard to know how much cash to have. Exact fare operators tend to have simple fare structures- NXWM charge a flat fare for journeys over one mile, Lothian only have one flat fare- which makes it easier to have the right money.
But if operators offer contactless, many of these people will simply use that. My point is that people who do still use cash a lot will more likely have change hanging around to use, but sometimes simply can't be bothered using or carrying it. I've seen it a lot over the years, they wave a large note to pay for a cheap fare, the driver says they can't change that right now, suddenly the change is found.
Did they cope any better or was it a case of having to cope as fewer people had cars? The problems are the same, you got on with a half crown coin and the first you knew about the exact fare policy or the fare required was when the driver refused to change it for a shilling fare. Now its just the same issue with a fiver for a two pound fare, but more people have the option if saying "**** it" and driving.
I don't think so, people just got used to having some change on them to use on the buses. It wasn't hard then, I don't think its got any harder now. And lets face it, how many car parks are there where you have to buy a ticket on arrival, and the machines only use cash? Same problem, different circumstances.
I don't think we really need to bother with change vouchers. It just makes it more complicating. We get given a large float before going out (a lot larger than what the big operators give their drivers) so it is only sometimes that we don't have enough change. Although i am sure we still get a few people purposely giving a £20 banknote for a £3 fare hoping to get a free ride (and they probably get disappointed on the times when we do have enough change on us).
I also think as Bletchleyite says it is a friendly policy as well. Sometimes people only have large banknotes on them and refusing them travel isn't really good customer service.
Contactless does make things easier for people with cards but i think a lot of a smaller bus operators won't want to spend all the money upgrading.
Where i work we are still using the Wayfarer 3 ticket machines which have no contactless capability and we have no plans to upgrade. I think a lot of smaller bus operators won't want to spend all the money buying newer machines to accept contactless payments. For many bus companies there are a lot more important things to spend money on.
I'm afraid if smaller companies want to continue to compete in the long term, then they really need to start thinking about electronic payments including contactless bank / credit cards. Its rapidly becoming a standard method of payment for small transactions for a lot of people. And certainly here in West Yorkshire all operators must be able to handle at least ITSOs, as many Metro season tickets are only available on these. It should only be a small step from there to being able to handle contactless cards too.
Times change.
People use cash less, so are much less likely to have changing floating about.
Bus fares have risen, meaning even single journeys are now much closer to the value of a note than a few coins.
And I'd also question the idea of "people coped in the past". That phrase is often used by people to complain about anything and everything in the modern world. And the usual answer is that actually people didn't cope. For more serious things (e.g. mental health etc) people actually suffered greatly. And for less serious things like bus fares, people have to deal with inconvenience and getting ripped off (especially where exact fare systems were in place).
And this brings us neatly back full circle, where contactless is available those who rarely use cash can use that, and where operators don't they might want to start thinking about it because otherwise they may start to lose business.
