Humans are social creatures. Being in a crowd is preferrable to being the oddball who has set themselves apart from the group. This applies on platforms and in carriages.
People are also pretty smart. Why bother moving in advance, unless you know for sure the place you are standing will mean you are trapped like cattle?
Most trains are not crush loaded either, and if there's really a crowd, you invariably have time to move down the platform once the train arrives and you can see with your own eyes whether your nearest door is not ideal for a comfortable journey.
In extremis, trains also have gangways now. So you're never stuck for a seat if the train does actually have empty seats at the far ends. For a long journey in a less than full train, the best seat will always be a walk away, wherever you stand.
Many people are also lazy, and many train journeys are pretty short. So why waste valuable seconds, often a minute or two, at your destination walking the full length of a platform, just so you can be that guy who likes to travel in seated solitude?
Last but not least, even experts like me, who used to be able to reliably tell even in unfamiliar stations where to stand for the frontmost and thus emptiest carriage, are now confronted with such a myriad of signage and markers, it's not worth the effort.
Most platform announcers seem to have no understanding of human behaviour, wierdly. If you cannot give people specific and clear instructions in a chaotic place like a station, you should expect to be ignored. Rightly so.
I would prefer announcers who are minded to nanny travellers, do something useful for the competent but not anal among us. Remind people with luggage or large groups, that where they are standing is unlikely to be their carriage on this very long train, so kindly ask a member of staff where they should be standing.
Or better still, stick to doing your job, and maybe ask a manager why ths staff on the platform aren't properly engaging with the most likely cause of delays when boarding. Because they're rather obvious to anyone who travels by rail regularly, and you would hope, staff.
I take the train a lot with a bike. Not once have I ever heard an announcer do anything remotely as useful as a simple thing like letting me know if the bike space is at the ends or the middle of the unit. And you surely know. Even on a two car service, it can be annoying to have to rush to the correct door, while all the other foot passengers are doing their thing.
I've got eyes and a brain. Tell me the door is at the ends or middle, so that as it approaches, I can stand back away from the disorganised rabble getting off and on, and then make my entry after they have got themselves sorted, without having delayed the train, specifically the ever impatient guard, by even a second.
Even then, I still have to contend with issues like people standing in the spot reserved for bikes. But this is the UK, we aren't smart enough it seems to make announcements of the form "please do not stand in the space reserved for bikes, because if you look behind you, that chap has a bike, and he isn't on this platform for his health, not with thsee stinking roaring belching diesel units we call trains, he actually wants to go somewhere, and in our wisdom, even on this service that hasn't been crush loaded since Victorian times, we still only provide two bike spaces per set, and you've got pretty much the entire train to recline in".
