The "big two" in ticket machine technology 40-50 years ago were Wayfarer and Timtronic. Did these makes just die a natural death or do any of today's machines owe anything to their late 20th century predecessors?
It's a sign of the changing requirements for operators that the two market leaders are effectively no more in the bus world. Wayfarer had a spin-off business called Bright Tech which pioneered electronic destination screens - Stagecoach being the largest customer in the early to mid 1990s. Wayfarer is still in the market, but is now known as Flowbird and they're the go to for parking machines and the like.
Most independent operators came to ticketer before the big firms did - c2011 onwards. Reading was the first 'big firm' to go for Ticketer and Cardiff Bus either the second or the third in 2014 - before that their product was aimed at the smaller operator/local authorities.
@Citistar can reveal a little more about ticketer and how he replaced his Wayfarer Saver machines with them.
At the time the product came to market the concept of being able to see ticket level data as it took place was quite revolutionary. Wayfarer 2/3 and TGX machines ran off a module which needed downloading on a base machine at the end of the driver's working day. So you didn't know how much you'd taken on bus until 24 hours afterward. The backoffice software Wayfarer had (Merit) was clunky to use and the extracted data needed a lot of cleaning up before it made any sense. You would also have to make repeated requests for the software to be installed by them.... why on earth would you want to know how your bus network was doing if you worked in a commercial office
Even once you'd got the data downloaded you still potentially didn't know what your takings would be - as data packets would go missing. Wrightbus Streetlites when they landed at Yellows were culprits for this - as they didn't download before the bus had the master switch turned off. You could hit 4 buttons on the machine and have it download that way, but that was something like 130+ machines to follow round.
Yellow Buses went for Wayfarer TGX machines in 2009 to replace Wayfarer 3s. The TGX machines were owned but there was a repair/maintenance contract in place - all machines had to communicate with the aerial at the back of the building so they ran the current version of the software. So if your senior aged school buses had a couple of weeks sleeping at the top of the yard you needed to fire them up before they went back after the half term.

Hence how I know Volvo Citybuses respond to a jump starter pack and that you should also work rear to front of the line (otherwise you don't see your colleague waving in the mirrors because of the smoke cloud you just made). Much fun was had getting them to arrive and repair machines.
If you ran outstations, you could have more fun with modules. Western Greyhound in their heyday outstationed a lot of the buses, but not all drivers would work into Summercourt. Some Liskeard drivers didn't at all - but their takings and module would be sent over in a bag with a replacement module going the other way. You don't want drivers having two normally! Go back to the 'second Setright machine' of old. Wayfarer Savers would be even easier to fiddle - to issue the ticket, press pound sign, type in the fare. It wouldn't drill down to fare stage/stop level.
As Ticketer downloads over cloud software you eliminate that need for trips to a mother depot to pay in and download etc. Yellows were very dissatisfied with Wayfarer by the end - and had been for 3/4 years prior to switching to ticketer. The need to go contactless accelerated it, as did an incident in September 2017 when someone other than the company rolled back the version number on the machines. That was a fun Saturday as 100+ buses didn't have working ticket machines. It is possible the air might have turned blue that morning. And yes, the entire fleet operated on emergency tickets as issuing an instruction to 'let them travel' was a bit hard for people.
Almex had an even more disastrous time implementing their smartcard enabled ticket machine - First went for the Optima nationwide and ended up with a lot of doorstops retired very early. I could have had a free one but didn't have a door needing propping open.
I guess it's a classic example of a market leader not keeping up with the developments in the industry and being overtaken by other new providers. Gardner used to be the preferred engine supplier for most people's buses but they never built them in sufficient volume, so people went to a firm called Cummins instead.