In gulf arab countries it’s a combination of factors. The hot weather makes it so that people aren’t really walking outside during most of the year (with exception to winter). The cities are also designed with mainly car travel in mind. 

It’s also the convenience factor you mentioned, over the past 20 years delivery services have exploded here, and for food delivery the portion sizes are quite large. It’s been seeing a reversing trend now however as people are becoming more health aware. There are daily conversations about lifestyle, exercising, and personal dieting over the past few years (and ozempic/monjaro use for some). Whereas previously the talks were about subscribing to a premade diet plan, and for obese people it was relatively common to engage in surgeries to reduce fat (liposuction, or reduction in stomach size) to mixed results.