Um, no it's not impossible. I have gotten as much as 100k oil on a single training blessing (1 hour), it's very doable if you know what you're doing. My typical take is about 70k-80k per hour with TH raiding with training blessing - which are plentiful now with marco polo troop chests...
If you set your base up right you will not get attacked as much, but if you're not doing it right you will get attacked all night long. You can't stop all attacks, but you can deter most of them, or force them to use tactics (decoy or sab) to get your oil. And yes, you CAN take down 3 TH if you set things up correctly. Just understand how they behave - there will be an initial drop point, and then a rally that tries to avoid your AA, towers, castle, etc. Remember that defenders also attack TH, and that your TC with howitzers will drop them immediately. There ARE ways to do this.
My advice is to get yourself some TH yourself and join the party. Once you're on the attacking end you'll understand why we love them. FWIW I don't mind too much if they're nerfed a bit, I'll still use them and get nearly as much oil. And many here will still complain it's not enough...