I think the way some people think a chicken will last several meals, (and others don't) does highlight that people have very different ideas of portion sizes.
I also cooked roast chicken today, about 1.4 kg, cost less than £5.
I have earmarked the leftovers for 2 more meals for my family of 4.
Point is, I never serve big portions of meat, the main thing will be the potatoes and veg - or in the future meals the rice/pasta and veg.
I think that's quite an old fashioned way of cooking now. Of course, it isn't necessarily cheaper now, fresh vegetables can be expensive. My grandparents used to grow all their own.
Or else people aren't very good at stripping the meat from a chicken - I genuinely get loads!