I think it's situational, the beemer I just picked up is 10 years, 44k on the clock and so far, not a single issue has been brought to my attention.
I don't think you can read anything into the fact you've had a 10 year old 3 Series for 1 week and it's not broken yet.
It's common sense - nothing lasts for ever and stuff wears out. The older a car gets the more likely it is to require both preventative and reactive maintenance and repairs, especially if it's received very little throughout it's life which many cars manage to up to the 10 year old mark (Especially low milers, people are obsessed with mileage and will think nothing of driving around on worn 10 year old suspension components because hey, its low miles).
Now this is absolutely fine as many people buying 10+ year old BMW's know this. They know it has the potential to turn into a labour of love. They know it might need money spending. But they are content with this because they'd rather incur this expense and hassle yet enjoy what a decent BMW has to offer over buying something newer and less interesting to own. But some people, generally those picking models which when new were purchased for economy reasons, just want reliable transport with low running costs and a posh badge and a 10 year old 320d doesn't offer this. If somebody is after a reliable, economical and cheap to run car for £5k then IMHO a Seat, Volkswagen, Ford, Honda, Toyota or often even a Vauxhall is simply a better and more sensible choice. And sensible is what matters because lets face it, nobody really buys a 2 litre 4 cylinder diesel because the heart told them to do it.
In fairness, I did spend double your budget Lynchy.
His budget appears to be up to £5.5k (One of the cars is this much). If you really spent £10-11k on a 10 year old 3 Series then that is completely nuts. No wonder you are so defensive if thats the case
Also, I am trying to make the point that baby Fox loves to argue everything.
This is a discussion forum about cars. I post here because I enjoy engaging in discussion and debate about cars, and for no cars is the case more than BMW.
Even when people ask for advice. Take that poor chap a couple of pages back asking if buying a low price beemer was good, posting about 8 links to cars he found. Asking for advice and little foxxy jumped on the poor guy...
I think you are taking the internet too seriously with terms like 'jumped on' but that guy had a very unusual and specific requirement for a car with under 20k miles on it but a budget that doesn't generally lend itself to such low miles. As a result all his examples were either very old, very poor specification or a combination of both. Why would I post 'nice examples m8' when I genuinely believe that all the examples he bought represented poor buys? Insisting on under 20k miles makes sense perhaps when buying a 1-3 year old car but when you are looking at 7+ year old cars not only will you get completely ripped off by the comedy price premium they attract, a car that has barely been used for 7 years probably has low-usage related issues anyway. It isn't good to hardly use a car and you get nothing extra for your money buying a 20k mile 07 plate over buying a 40k mile 07 plate! They are also a significant depreciation risk because once you start actually driving it the miles pile on and it loses both it's expected depreciation and it's low miles premium.
People post here for advice not to have a bunch of yes men tell them how wonderful what they want to do is - at least, you'd hope thats why they post, as the latter helps nobody.