> So he will continue using Nagios because it works well for his use, and good luck making something better.

Ops guy here. If something better than Nagios/Zabbix came along, ops people would use it. Nagios gets used because 1) people know it and 2) its pretty easy to setup.

Is it going to scale to Netflix or AWS scale organizations? Probably not. But at that scale, I presume you have buckets of money to throw at problems (i.e. build a custom monitoring platform).