John David Galt wrote:

The tiny trickle of people using bikes could increase
by a factor of 100 and they'd still be less than 1% of traffic, hardly
enough to justify robbing the majority of even a single lane.

That is your claim, but observation, at least here in Europe, shows
otherwise. Number of people riding to work, school or shopping is high,
up to 2/3 of all travels in some regions.

So cyclists are allowed to ride in crosswalks in Europe? In the US this
is illegal (unless they dismount first) but commonly done anyway, often
by pulling out in front of cars as if the biker had the legal status of
a pedestrian (which he does not).

This would happen on crossings with traffic lights. These have symbols
for pedestrians, cycles and "other traffic", and you do what the lights
tell you. Within cities bike paths are more often than not segregated
parts of the sidewalk, thus the cyclist quite naturally behaves a little
like a pedestrian.

I take it that Europe does not allow the car driver to take the bike
lane a few metres before the intersection, thus preventing this
conflict? (In California this is not only allowed, it is compulsory.)

No, cars have nothing to do on a cycle path over here. In many cases,
construction of cycle paths make such behaviour impossible, too.

That's what happens
if myopic fools disregard the question of sustainability.

Sustainability my ass. That's what happens when NIMBYs stop the process
of expanding the road system (which of course needs to go on permanently
as long as population is growing) and then blame drivers for the resulting
congestion.

This sort of red neck car driver attitude does not get you anywhere.
First of all, population is shrinking, not growing in most western
societies, only the number of cars is growing.

Second, experience shows that building new roads does not solve the
problem of congestion, because as soon as a new road opens, it gets
clogged by additional traffic. Streets claimed in the '60s and '70s to
solve traffic problems "until the turn of the century" were clogged 2
days later (London being one example, the "Ruhrstauweg" another).

Thirdly, appart from financial considerations there are other limits on
road building. Pollution levels and land use for roads can not be
increased indefinetly, in particular in the densely populated areas of
Europe.