Smudge has posted some interesting thoughts on another thread.
"My maintenance efforts go effectively on one bike as well rather than being divided between several (none of which end up getting enough!)"
"On a bicycle especially, if parts corrode/wear out, then it's a good reason to replace it with better"
This was in response to ruggtomcat thinking about getting a cheap bike for the salty winter.
There are plenty of people on here with more than one bike. Some will probably only get ridden on dry sunny days.
Since the 'invention' of mountain bikes and their use in mud I think ideas about use/wear/maintenance/replacement have changed. Cleaning too.
I remember at the first MTB race I went to seeing a successful racer with a bucket and a brush removing the mud - especially from the transmission. Most were happy to just load their bikes back on their/parents' cars.
Commuters value reliability, so spending a bit more is probably a sound investment. Better bikes tend to be more pleasant to ride too.
Some people do their own maintenance on a preventative basis, others just ride until something fails.
To some extent this relates to the Does anyone calculate their cost of cycling? thread, but 'best you can afford' or 'something cheap for the winter' seems to be a philosophical question(?)