I wondered when this rant would come up.
Put simply, other places in the world get much more snow on a more regular basis, so it makes more financial sense for them to invest in posh expensive snow-clearing equipment to continue normal operations. Here in the UK such events are pretty rare and as such there isn't the business case to spend hundreds of thousands of pounds on snow clearers that sit unused for 11 months of the year rotting away with flat batteries and siezed engines and driveshafts and de-icing fluid that goes off because its not been used and is therefore unusable (did you know that? De-icer fluid has a shelf life? Thought not.), which then all costs a hell of a lot of money to put right again... It's actually financial sense to accept that for a very short period of time things will be disrupted but then the world carries on as normal after said short period of disruption has passed.
As for Heathrow, it will always struggle, because it is at capacity. Any small thing will thus completely stuff everything up.
But hey, without understanding all this it's much easier to have a good old rant on PPRuNE. Hope you feel better now.