Everything that Dave highlighted is absolutely spot-on.
However, I would suggest that not everyone is a PPP (Penny-Pinching Plonker) but many are just a CCC (Cost Conscious Customer) and will continue offering the following viewpoints.
1) BT's Redcare is unreasonably expensive because only they can offer the benefit of the remotely fault-monitored line. This includes on-going regular charges as well as initial costs. Customers hate not having a competitive choice.
2) Paying for two (or more?) BT Redcare services is not really cost-effective when the original monitoring service was designed to handle up to 8 different alarm warning signals on the same line, not just one signal. Why buy a car capable of seating eight people and then being told that if you and your wife want to travel to the same place, you will each need your own car?
3) Distrust of industries, manufacturing and installing high-tech systems, that seem to be unable to come up with a simple solution acceptable to the technical and operational requirements of both the fire and intruder industries. The existing multi-Redcare solution to the problems financially benefit BT, the equipment manufacturers and the installers only. Customer's hate being 'oversold'.
Until we can offer a usable integrated solution I can't see CCC's being impressed with the supposed benefits of arc monitored fire systems.