If those running NHS England and other health politicians, medics et al are solely motivated to elevate people from a passive infantile attachment to the healthcare machine. They might spare some focus for poor posture.
After years of seeming to belong to some quaint past, people have been instinctively picking up again, with nary a peep from from our unquestionably benign patrician establishment.
Sports people increasingly use posture braces and wear t-shirts with built in aides to hold the body in better alignment, whilst on the move, which is a step on from the adjustment of standing or sitting. That gives a potential public face to raise awareness among people, without the necessity for coercion of either party.
I remember cottoning on to this many years ago. It came into play when too much of my rather overwrought desire to improve/support my health was going down the drain, due to the cul-de-sac of weight loss dieting and exercise as a vehicle for it. And whilst I do not claim to be an exemplar, far from it. I'd say without the level of awareness I have, I'd be palpably worse off for it.
I know other fat people (as well as others) arrived at the same point for the same reason. Depending on how your body's shaped, higher weight can make it seem more of a challenge, due to the pull weight can exert but don't let that put you off. It's possibly more rewarding for fat people to take care of their posture.
It's one defense against succumbing the burden of the 'obese' construct, which exerts a physical as well as mental toll. A lot of the things fat people are supposed to have, bad knees, hips even things like joint pain are often the cumulative effects of bad posture and mis-use, ditto for others including thin people. Consider why so many people require one hip or knee to be replaced.
Use. The way you use your body, your habitual posture, stance, gait. That goes for fitness related injury too. Usually the dominant side that goes first-i.e. if you're right/left handed.
This is all challenging enough which aids mindfulness and patience, force is likely to cause harm or impose more strain.
It's pretty obvious that this is a big influence on the extent of back problems. Ditto those who keep getting the same injuries whilst doing sporting or other physical activities. That's usually a postural fault or a problem with the way you use your body, and/or even your mind whilst you are being active. Other times its a physical kink.
Seeking to restore, and improve posture and use is accessible for most people, regardless of physical status. It challenges and increases our awareness of our bodies, rather than shifting more locus of control to the medical machine under the guise of "personal responsibility". It reminds me a lot of the aims of HAES, which was a therapeutic desire to keep and restore function to fat people abandoned by the medical system. You have to start from a place of acknowledgement, preferably acceptance and work from there.
Above all, it's positive. It seeks to liberate rather than to constrict in preferred pathology. Even just regularly visualizing pulling up a string coming through your spine and out the top of your head, is enough to help to begin the process of re-training the way you hold yourself.