I don’t listen to music on my AVR. I have a Sonos for that.
What you’re talking about is totally impractical for most homes.
Explain how device with more hdmi input and output and standardised components , better build quality is impractical for most homes
If my speakers blow up I can simply buy any standard passive speakers connect back up.
If a subwoofer blows up I can replace it with any standard subwoofer
If my avr blows up I can replace it with any standard avr
I can listen to music on my AV system and it'll sound better than a soundbar. Also when you mention Sonos I have a wiim streamer connected to my AV system so can listen to that.if I want to change the streamer I can. Add a bd player, Kodi box etc as it has enough hdmi inputs.
Sonos speakers wont have the sound quality either I presume you're talking of the portable rechargeable speakers?
Soundbars are good but they won't come close to seperates proper system, sorry
Also you have options on speaker design. White, wood and different veneers, gloss, bookshelf, tower, the number of speakers, inwall, onwall, subs either sealed or ported, driver size, single/dual driver etc. different sound signature, whether you like it soft on treble or bright harsh speakers
Also as audio codecs change you are stuck. You have to ensure your TV passes all the codecs, because if it doesn't you only get pcm. I plug it direct though AV pre, so it doesn't matter what the TV arc/e-arc and codec support on that is. I updated from Dolby digital /dts 7.1 AV pre amp that didn't even have hdmi, to Atmos/DTS X 9.3.4 AV pre amp, keeping all my speakers, amplifiers , cables in place. Didn't need to throw the lot away. Also I added extra speakers and amps to go from 7.1 to 9.3.4
Then choice of speakers with built in upfirer or place on top of speaker upfirer, or on wall height speaker or in ceiling.
Then choice of multiple subs if needed typically avr support two, I have option to go four all synced with subwoofer dsp box.
Someone with a avr and stereo speakers could go
2.1
3.0
3.1
4.0
4.1
5.1
Plus 7.1 and above.
I'd say long term seperates is worth it, you don't need to go OTT like I've done
But something like wharfedale diamond 5.1 htp or q acoustic 3020i system good first system and gives you expansion choices later