I live in hope too, but here's my reasons why not:
1. General laziness and apathy. We now have an entire generation of kids who have grown up under the Thatcherite 'cars are good,make you free, public transport is bad and run by communists' philosophy.We copied the US (sorry to US forum readers!)in terms of transport policy ie. cars are the future.
2. Glossy expensive surreal car ads that make most 17 year olds want to buy a car five minutes after they turn 17. People are wealthier nowadays, some even buy cars for their offspring!
3. Crap cycling infrastructure. Ok, some bits are good (Bristol Railway Path..yaay

!), but we're light-years away from the Netherlands

.
4. Cars rule. Towns and cities are designed for them with little thought of anything else.
5. Anti-cycling right wing Tory press. Bristol is a cycling city but we are cursed with the Bristol Post, a chip off the old Daily Mail block - the DM once tailed CTC president Jon Snow through London trying to catch him RLJ'ing etc.
6. No money. Funny how we can't afford cycling infrastructure and have to scrounge/beg for every penny but can afford illegal oil wars in Iraq. Boy, would I like to be left with Tory Blair in a room for five minutes
Some of you might disagree, but these are my thoughts......