Too many companies seem to work like (some) students before an exam. You may know when the exam takes place months or years in advance, but you only start revision the night before.
And then you have people who don't personally, at least not at the time, have a need for something and so think it's fine to not have it. They are happy to ignore the needs of others who do need information to help them get about and live normal lives.
When it comes to government Regulations, you have to have certainty on what those Regulations are. Whitehall have been lazy and just copied TfL's ibus standard, which requires every interchange stop to be announced. So when your bus runs parallel with another route for 4 miles, it has to be listed and announced each and every time according to the regulations "because bruv datz ow eet works in London m8". Some city centres might have 40 routes along one street - those all have to be announced?
Buses also have to be fitted with a telecoil loop, which means taking the interior to pieces, often wasting interior panelling. It isn't really feasible to test this without specialist equipment (hearing aids cost £500 a pop, telecoils are an old technology likely to be replaced).
That last one is a massive cause of delay as buses are a volume industry, you have to do the same thing hundreds or thousands of times.
There isn't a list of approved suppliers which means the government hasn't done any work whatsoever to define a standard to help suppliers, or even understand what is and isn't necessary (or possible), or how London's needs are nothing like "the provinces". It has chucked operators into the deep end, added an unreasonable time limit (3 years for 7,000 buses) and has left enough room to change their mind to drive a bus through at a later date because of the vagueness of the rules. Only when the Regulations are on the statute books can any work actually begin as they can't change the wording, but they'll change the context if they can knowing Whitehall.
It brings to mind this scene