Just on the above, I would think that that chances of having a power socket on/near the "back" wall would be quite high though. This would still be a lot better than having to run speaker cables right around a room - I'm thinking it's not even possible in my case, it would have to underfloor/in ceiling.
Also, while being in a very exclusive club, the JBL rears are actually wireless. They dock with the bar and charge when not in use - I fully understand that they don't have the fidelity of proper AVR surrounds but they work surprisingly well.
I would like to add to this regarding the wireless rears. They seem to work fine in my environment and are for obvious reasons extremely flexible in placement with only the caveat of making sure the upfiring drivers are not blocked. I also bought a couple of cheap portable batteries to power them for longer over the weekends, but docking them at night during the week is hardly a chore.
My time so far with the JBL 9.1 shows that I would dearly love to have an AVR set up, but just don't want the additional furniture and cabling, that others have spent quite a bit of money getting hidden one way or another.
It will take a while before sound bars can reproduce at full size set up levels and even then won't keep up with floor standing based sets with monster subs, but I am certain they will improve and get better battery powered rears, which will make them a match to a certain degree, which is what I am waiting for, whilst using the JBL set up in the mean time, gives me surround and overhead to a satisfactory degree. However once the Soundbar systems get 7.1.4 with better sound quality and battery powered rears that are the size they are now, then I am up for paying more than I did this time round.
It really is a case of what best suits you and your family, plus your home, as to which is the best, but if I were to put my neck out I would say AVR every time, even though I have gone the soundbar route.
Soundbars will always be behind in my opinion due to the limitations of the drivers. Hopefully technology will overcome it, but physical size is a hard one to beat.
For what it is and how much I paid for it, the JBL system is good value and a reasonable compromise for me. TV shows in particular are benefitting from the system, such as the Mandalorian and the Expanse.