Fox is like the Quentin Wilson of Motors, only he talks sense about decent cars.
Even ones he has no experience of?
I ran mine for two years, yes it was expensive, but I was not kidding myself that it would be cheap to run over the period of time that I owned it. Anybody looking for a cheap run about should not look for a BMW regardless of model tbh.
The e39's cooling system is weak, that said, the system on my Dads 528i has not (yet) exploded after 11 years. Again, no such issues for my e38 thankfully.
Tyres are expensive, but again, they will be on any car thats running 18's.
The OP wanted something, by the sounds of it, large & with a big boot & great for motorways with no worrys about fuel.
The saving in fuel should more than compensate for the potentially high running costs, that said, from my own experience of BMW's, buy a good one and it won't cost you the earth to keep it on the road.
The trick is finding a good one alas.
As for selling my car, well, my circumstances changed. When I bought my e38 I was living at home with my Parents after a relationship breakdown, so obviously,bringing home £500 p/w and giving £60 "board" ment paying to run a BMW was not an issue for me.
2 years later, I have my own house & bills - you'll get there one day Fox - and surprise surprise, running a 7 series was no longer financially sensible to me at all, add to that I promised my GF a holiday at the end of her Cancer treatment, and something obviously had to give.
Things are different again now for me, I can afford another e38 and am looking for one but, tbh, the sheddy Mondeo I've been running since selling the e38 suits my needs perfectly - it gets me from A to B.
Why I am justifying myself to somebody who does not yet live in the real world, I don't know.