The problem with jumps sires is that it takes so long for their progeny to get to the track that, by the time people have started to notice them, they are often in the latter stages of their careers, or dead!
The stallions you mention never covered very large books of mares, so arguably the quality of mares sent to them was pretty low, hence taking time to get a good horse.
I've no observations about NETWORK at this stage, but MONSUN is without doubt a great influence. His horses are big, tough and very sound - ideal attributes for jumping!
Watch out for his other sons in the NH sphere in the coming years: GENTLEWAVE, GETWAWY, MANDURO, SCHIAPARELLI and SHIROCCO.