It is physics for speaker size - you need a large speaker to create bass and move air hence a sub. Clever porting and engineering creates a large sound from small enclosures but as this requires money and investment, it doesnt happen much.
The drivers inside the sound bars are identical to those in the flat TVs. Its only the inclusion of a sub that generates the low end adding back what a driver inside a decent enclosure would do. As before, Sony do a NFC subwoofer so even the sound bar is redundant.
And dont forget, a soundbar is just a crap box with crappy small drivers in it usually mated to an equally crap sub with a pissy 6" driver trying to do the job that two shelf speakers can do far more efficiently - its the bullshit baffles brains of ooh its wireless - big whoop - as already shown you can make anything wireless for the price of a couple of downloads.
Its the £69 'mountain bike' all over again.
As for space - A sky box is now too big compared to what others can do. DVD player, redundant if you have a blu ray player and if your telly is 'smart' and wifi enabled, online streaming makes just about all the above redundant. More electronic waste that the fairies take away and magic to nothingness with no pollution whatsoever... Something that makes quite a few people itch over the waste of it all - just google where old CRTs end up.
Going back to making it sound good - a sub with a high level input will do a good job. you can connect anything to one of those via the speaker out. Then you can run small shelf speakers wherever you wish, cat friendly, child friendly and most definitively wife friendly.
Wireless speakers are getting cheaper for surround sound film fans so wires are no longer the issue they were.
Its all there for those that want to but I guess the Argos catalog is too easy.