3....Why don't fanjets have variable pitch blades like the turboprop has?
Fair question. VP blades would give greater efficiency over a wide thrust range, and the performance guys would love it.
But VP for a fan turning 3000-4000 rpm is a different matter than for a prop turning ~1000 rpm. It's another system wth failure modes to be considered. Airlines are in an approach-avoidance mode re variable fans; They like the fuel efficiency, but fear the maintenance requirements and impact on dispatch reliability.
BTW, newer turbofans DO have fewer, and bigger, fan blades than early engines. Count 'em.