My two prior homes were both wired with Al wiring.
The first, an upper-end home, was purchased directly from the prior homeowner when the renters vacated which turned out to be an advantage in the respect that they didn't bother to paint, especially around the outlets that had fried. This gave us the 'heads up' that we needed to pay close attention to the Al wiring issues. We were advised (by whom I have no idea) that the solution was fairly easy; replace any burnt components, add Cu to Al connectors on those that seem 'prone' to frying and tighten all the rest. We, harry homeowner, did as advised. We also had an FBN (fly-by-night) guy add a three-way switch at a split-level hallway juncture, just as you say is likely to happen. When we sold, through a realtor, it all passed 'inspection' and sold nicely.
Second home was a tract home (minus a husband by then), and the home inspector pointed out to me that the Al wiring looked pretty nice due to the fact that the developer in the late '60's had 3 electricians. One of them did an A+ job and the other two did A jobs, my house got the A+ guy and the inspector said since the electrical stuff looked good, felt tight and showed no evidence of frying, he'd suggest leaving it alone save one outlet that didn't work at all. For that, he said have the realtor (who owned the home, by the way) pay for the fix. As advised, I pushed that one back to the realtor who said she'd send 'her guy' over to fix it. 'Her guy', as I've described here much earlier, was also FBN-ing around his day-job w/ a licensed electrician and had to schedule his FBN-ing around his community service & DWI jail time. I really, really would've been more than happy to invest my profits from the sale of the first to re-wire the whole house but was deterred from going that route by the home inspector - a lesson learned.
As a homeowner, I think people ARE resistant to hear that the 'fix' might entail stripping out and replacing the entire electrical infrastructure at significant cost. However, I don't think that the average homeowner really understands the risk issues, namely the likelihood that the risk is present and how large any problem could get very quickly should the system overheat or overload. (Hope I said that right.) If, somehow, there could be a way to relay the details of how important PREVENTION is vs. having to deal with a real crisis and introduce the probability into the discussion, it may actually land on hearing ears.
As a result, I hate Al wiring and am loathe to ever have to face that possibility in another home. It's too much to have to worry over when you put your head on the pillow and hope that you'll be able to avert disaster for yourself and 3 children.
