I have never seen an older 560sel or 600sel nor a 750il or 760il to be fuel efficient and they were severe competitors of Cadillac and Lincoln in the 80's till even today. But you can't have everything. Even back in the late 60's-early 70's, a chrysler imperial or a cadillac fleetwood scored as much regarding mpg (10.00 to 12.6 mpg).Also cars of today have much more electronics and assistance in every aspect. Where I live gasoline is expensive (nearly 1.23€ the litre of unleaded 95/98 octane gas) and there are laws that have been implemented which ban cars older than 10 years old to cruise inside Paris.