Most hospitals do have schemes to help immediate relatives of long stay patients, but they probably aren't great at letting people know about them. Parking is a huge problem at most hospitals, because of the large numbers of staff that work there. I have yet to work in or visit (professionally) a hospital where parking wasn't a major gripe for staff. It is worth thinking about the sheer volume of people who want to use the spaces. The teaching hospital I last worked for had 2000 staff and something like 500 beds, so if you think about all the potential friends and relations there is a huge demand. In the middle of a city there simply wasn't room for a car park that would take that volume (bearing in mind that most hospitals are on sites that pre-date car ownership for the masses as it were). So the prices are there partly to try and manage that demand. Then of course there is the potential to make a bit of money on the car parking too (btw even where the car park is managed by a private company the profits will not all go into their pockets, unless the land and building costs were born by that company it's most likely under contract, or a partnership deal). Hospitals in rural and out of town areas should not have the same problems.
Regarding the food, in my experience bulk catering is usually rubbish, but the NHS should be doing better, and does it is fair to say, try. But the money put into food is still very small, because in the competition for resources catering usually loses out to the higher tech and higher profile services.
Services such as coffee bars etc are almost always provided on a contract basis, again as a way of making a little money, and improving the experience for visitors. It wasn't long ago that they were all McDonalds, so there has been some improvement on the healthiness front.
Many hospitals are running in tight financial circumstances, so the little things that would improve your stay have fallen by the wayside (many of these were provided by voluntary organisations in any case).
But it was not that long ago that parents were not allowed to stay outside of very limited visiting hours, so some things have changed for the better.