The 1st paragraph spoke of yourself with the 1st security setup.It's not so much about the cost of something but rather more about how one configures it and their knowledge of potential attacks, threat surfaces, etc. You can throw 100K at a network and still be wide open to a variety of attacks and intrusions. No offense but if you knew anything about network security you'd already know that - and you would already know there isn't any functional UTM difference between a 200K Fortigate and a $500 Fortigate, it's all configuration. A 200K datacenter Fortigate difference is simply throughput and processing power over the smaller cousins but both have IDENTICAL protection systems...
I'd be very surprised if more than a handful of homes in this country have an active sandbox appliance in place. I'd be even more surprised if ANY homes had a secondary security appliance in transparent mode, and I have only seen one corporate network with a transparent behind a primary and that was a defense contractor. I also utilize the Fortinet Security Fabric (FSF) which is quite new - a few months old and is specifically designed to intercept advanced persistent threats.
Can I still be hacked? Nobody in IT will ever make a 100% guarantee about anything, including me. But the difficulty of breaching and compromising my systems would largely exclude anything but a well financed state actor with a high degree of persistence. A state actor would most likely just compromise one of the network hubs I connect to and be done with it... For anyone else (Hackers, hacker groups, contractors, foreign state actors, etc) Persistence is the key here, if they want in they will keep working at it, patiently, and watch for mistakes, exploits or vulnerable programs/systems and exploit those to attack me. Having multiple layers requires multiple compromised systems, making such a thing much more difficult. Active monitoring (SIEM) makes it even more difficult because everything is monitored and activity is discoverable via a single pane of glass giving them even less time to perform activities.
In another thread I explained in detail how to lock down a cheap commercial router. You don't need superhuman gear or knowledge to have a good solid WAN from all but the most persistent thug. I'm an enthusiast, and do this for a living so that's my reasoning. (aside from the fact I've been regularly targeted in the past)
Do I have a sandbox installed. Yes, I do and is it active? Nope.
You have being targeted is because you are outstanding and not because you are just a normal home user. That's for sure. If you do not go around and reveal your set up I believe you would be much much safer.
Like I mentioned it's not just a hardened layered security system but the RIGHT hardened layered-security system that counts.