You must've been accessing some shady and malicious websites to be targeted like that.
Nope. An attack can occur on Twitter, YouTube and Instagram. In fact, it can occur on any website the hacker wishes to monitor on its users. You'll be amazed by how much info they can get from you. They can even have access to your mobile phone and turn it into a listening device.

I've never have to change credit cards due to fraud...
I guess you're not of interest to them.

Watching too many conspiracy movies? But let me ask you... how do you work with your personal or work data when mobile? You bring two devices? One offline and one online?
Are you still studying?

When mobile, like at the airport, I simply call my agent in Hong Kong to prepare the contract for the factory in Chaozhou and have it faxed or emailed to me. I'll sign it later or he can sign it on my behalf.

People can do the work for you in the office you know. Lol

Air-gapping actually makes it more difficult to work on something. You lose productivity moving from one computer to another. Time is money. The best is still to follow online security best practices plus using a decent firewall and endpoint protection.
Sorry, it's just not the case for me. I can still work fine, no problem. How hard would it be copying files from USB to USB? Thanks for the advice though.

Firewall? Anti Malware/Spware/AV? Are you kidding me?

You know how much time is wasted cleaning the virus or malware? When you thought you've cleaned it, it pops up again in your browser. You don't know what files it has infected in your system. What is worst is that after cleaning, your system does not work fine anymore. Either it freezes on you or simply too slow to work on. You then do some troubleshooting and hairpulling. The best remedy for this is to simply nuke the hardisk and start from backup. How many hours wasted.

You talk about productivity loss, this is productivity loss.

Anyway, there had been not a single breach. There were a couple of attempts before which was caught by Untangle's IDS/IPS and another by pfSense IDS/IPS (prior to switching to Untangle). But even though I am less restrictive compared to what you're proposing, I also keep an "assume breach" mindset and if such an event occur in the future, I've got the daily and weekly Windows backups to recover from.
If you think this can work effectively, why would Snowden use TOR?

Good luck on your backups though. I never have to do that anymore due to an attack or infection. I do it because the hardisk is going to go anytime. Lol!