It's tempting to say that some of the worst airports in the US (say Newark) are "third-world" but the truth is that a bad airport in the third world is often a lot better than any airport in the U.S.
This prof was talking about defects in the last generation 737
https://www.ithaca.com/news/cornell-expert-boeing-737-plane-...
https://boeing.mediaroom.com/2011-12-13-Boeing-737-MAX-Logs-...
-- Southwest orders 150 737 MAX airplanes and 58 Next-Generation 737s
-- Southwest becomes launch customer; scheduled to take first 737 MAX delivery
-- Largest firm order in Boeing history
Since then, they operate 223 of the 737 MAX (16% of deliveries) and have 495 on order, which is about 10% of total orders. At a single airline. United has 159 and has 388 on order. Then comes Ryanair with 136 delivered and 374 ordered. These are not third world airlines.
https://www.aerotime.aero/articles/25906-why-can-t-boeing-ju...
> In the early 2000s, the plan was to roll out the production model of Y1 by 2015. In 2010, Boeing’s patent became public, revealing a glimpse of the new project: a dream of all low-cost airlines and a bold new step for the industry. The aircraft was supposed to have T-tail and nearly elliptical fuselage cross section with twin-aisle 2-3-2 configuration, but retain drag-per-seat and weight-per-seat ratio comparable to single-aisle competitors. A variety of weight-optimization techniques, utilizing the newest composite structures, was explored. According to Boeing Commercial Airplanes CEO Jim Albaugh, the company was already looking into converting their plants from metal to all-composite manufacturing.
> But come 2011, the project was shelved.
Wikipedia says Southwest has the fourth-largest fleet in the world (today, dunno about in 2011); while that's a lot, that's still only 800-some planes; did Boeing really let an airline with a 7%-or-so share of their business hold them over the barrel? I guess that's not entirely unreasonable, but... it's not great.
And if you look at the breakdown, more than 70% of Southwest's fleet still consists of 737-700 and -800. Boeing in 2011 was "taking too long" with their next-gen plane, and yet, 13 years later, Southwest is still largely on the previous generation. Maybe their blackmail was more a bluff. Hell, maybe at this point they regret their blackmail; it possibly would have been better for them to just wait for a new plane, or not bother and just go with Airbus.
But really, the problem didn't start in 2011. They'd already rode on the coattails of the 737/737NG design for too long. They should have started on a new narrowbody design even earlier. Sure, hindsight, and all that.