Smash and grab, cutting cables, cutting coms etc... are all aspects that can be designed out of a system of a location or made extremely hard (if you're willing to spend enough time, money, knowledge) again cost vs reward. No-ones going to disable a grade 3 system, cut through 10mm plate steel and drill through reinforced concrete to get a £200 TV.
However as the cost comes down and you can download a tiny application and run it on consumer hardware that will essentially disarm certain alarm systems with a click of a button. With encryption what's unbreakable now becomes child's play as time passes. It sounds like some of the consumer aimed manufacturers do the bare minimum and can be bypassed with minimal effort/equipment, but the question is how advanced is the technology in the G2 systems and how long before they too become easy targets.
I guess your average home is never going to become a lucrative target for high tech thefts and anything worthwhile is going to be on a higher grade system and additional security procedures.