I think you're overstating the quality of ferraris, after all, I have yet to hear a Viper combust like
ferraris tend to do. Let's see...Viper causing paint discoloration next to exhaust vs Ferrari bursting into flames. Yeah, looks like the more expensive car has taken larger liberties with compromise than the lowly Viper.
A lot of people like the viper but would not buy it even if they had the means. It's really just personal preference. I have always liked the Viper but did not buy one until the Gen 5 became available. I could have bought any of the previous generations but it wasn't what I wanted in a car at that price point. It doesn't mean that I think a car has to cost a certain amount for me to consider it worthwhile...i.e. saying that a viper is somehow inferior to a ferarri based solely on price is just plain ignorant.
Money spent is never wasted if you're getting something you want when you have what you need. Your neighbor is guilty of poor planning and budgeting; not so much "wasting". Wasting money would be buying a car based solely on their price, regardless of what you are actually getting for the price you pay. The viper hangs with and can potentially defeat a $300K SLS in a race...shouldn't that $200K gap in price be worth more than a few tenths of a second? And the viper looks far better than the SLS both inside and out.
There's nothing stopping you from driving around in a Viper daily but it's not built for commuting. It's built for racing and the GTS is excellent for cruising...sitting in stop-n-go traffic would not be my optimal use of a Viper. Rather than talking about how often you use something, why not focus on how effectively you use it when you do. I think you'd get more out of a car like the viper by taking it to a race track every so often than you would sitting in commuter traffic and trips to walmart.