I think you're on to something. I've used electric dryers for decades, following the routine above, and never have had a problem. I strongly suspect the dryer was used without cleaning the lint filter before every use.
Nope. My wife and I clean our screen for every load. We get this same build up everywhere. It even makes it outside. Thankfully, we have a very short vent tube. Lint is everywhere in our laundry room (it gets cleaned, but it accumulates very rapidly). I just figured it was the cheap nature of the product (Kenmore Series 70 from 2005). I'll be looking into this loose-fitting pipe issue over the next weekend.
Well...First of all, I guess you didn't bother to fully read the post where the writer said that HE DID, in fact, clean the lint filter every time. One of my friend's house burned completely to the ground due to exactly this problem - lint accumulation inside the dryer where it shouldn't have been and catching fire. They, too, cleaned the lint filter every time but very fine bits went through the filter and settled around the dryer drum. Actually, contrary to your belief, if they hadn't cleaned the filter so religiously it might have been better!