For the VERY VERY frequent flyer, maybe 2-5% of the world, your analysis may make sense. 50 RTs a year? How many people do that? Yeah, I know there are some, but really.

We WN fliers are not nuts, I assure you. Here are some considerations:

1. WN has nicer employees; very few "dragon FAs."
2. WN is less likely to "go mechanical" on you at the drop of a hat (UA out of Washington, DC, I'm looking at you).
3. WN is less likely to lie blatantly to your face (UA out of Washington, DC, ditto).
4. WN doesn't screw you out of your fare when you make a change.
5. WN often has more RR awards available for your planned trip.
6. WN doesn't have computers that blow up on holiday weekends, screwing thousands of people.
7. WN planes are cleaner, from what I see.
8. If a fare drops, you can pocket the difference as a voucher good for a year (alone potentially worth thousands of dollars to someone who flies 1 RT per week). I'd play that one like a fiddle.
9. WN doesn't change its schedule ALL THE TIME and sometimes fail to get the word out. Read some of the threads running now about LH award segments getting changed and hosing people's plans.

I could do this all day.

For the person with less than enough travel to attain highest status on a legacy:

10. WN doesn't charge outlandish fees for luggage.
11. WN doesn't charge for last-minute RR redemptions (and some actually exist).
12. WN's Visa card is MUCH MUCH more generous than AA's Mastercard (not many people fly 50 RTs a year, so they have to get their credits elsewhere). $9600 spent on WN tickets or with partners gets a RT and 1/6 of the way to a Companion Pass; how much spending is needed on your AA Mastercard? A rental car can get you 2 WN RR credits. What do you get with AA, 100 lousy miles?
13. Double bonus credits (for example, to PHL and DEN at the moment). If you are lucky enough to live/travel there, it could be extremely lucrative.

A Companion Pass is worth a lot more than $800. Someone posted how he got $4500 worth of trips (for his wife, I think) out of it. I value it at $2000-$2500, maybe more, as I take my son somewhere about once a month.

Some of us don't fly Business Class to Hawaii and Cameroon and SIN all the time. We are pretty much restricted to the US for business and family reasons.

And what's wrong with flying both WN and AA, taking advantage of the benefits of each, as the case may be? Why does it have to be all or nothing? For example, I can see where it might make sense to use WN until you get 100 credits, then switch, especially when using the WN Visa and renting cars. Then you'd have top status in 2 programs.