In-wall speakers vs. bookshelves plus subwoofer for Stereo/HT setup

It does not have to be in-walls.....

Option 1 - On walls

MONITOR AUDIO
https://www.monitoraudio.com/en/product-ranges/soundframe/
https://www.whathifi.com/monitor-audio/soundframe-1/review

MARTIN LOGAN
https://www.soundandvision.com/inwallspeakers/708ml
https://www.martinlogan.com/en/product/fresco

Option 2 - bookshelves that are designed and made to placed on a shelf or wallmounted

REGA R1 / RS1 /RX1 ( model in succession)

http://v2.stereotimes.com/post/the-rega-r1-loudspeaker

”....Immediate impressions are a clear and transparent portrayal with very high detail retrieval, fast and controlled transient response, and superb musical timing, both in articulating rhythms and tempi, and in placing instruments within the temporal flow and context of the performance. The RR125 is an outstanding mid/bass driver, sonically and musically right in line with the midrange performance of Rega’s amplifiers and phono cartridges. Get the midrange right and everything else will fall into place. Get it wrong, and all the king’s horses…

The Rega R1 becomes my new budget reference speaker. In addition of its ability to get the fundamentals of music right, it adds clarity and resolution, and an ability to lay out a vivid and coherent 3-dimensional stereo image. In small room applications, what more could you want?...”

https://www.analogueseduction.net/rega-upgrades-parts-accessories/rega-rs1-speaker-wall-brackets-pai...

http://v2.stereotimes.com/post/the-rega-r1-loudspeaker

http://www.rega.co.uk/rx1-loudspeakers.html

Hi Alex. No, you are better off with Bookshelf speakers like Harbeth Monitors. It is difficult to control resonances in walls and it might even
increase transmission to the neighbors assuming it is an attached condo. The shelves have to be weighted down nicely. Put granite under the speakers and bang on the shelves to make sure nothing rattles any rattle has to be fixed or it will drive you crazy. It helps if all the shelves are full of books and records. Hollow spaces resonate. If there are doors make sure they have strong magnetic catches. I have heard reasonable decent book shelf systems. 

Bookshelves, for sure. Everything mijostyn says plus bookshelves you can experiment with placement. Something changes they easily move onto a stand. Or whatever. Point is, options. Not to mention they just always look a whole lot better.

For bass the answer is always four small ones. The smaller the space and the fewer the placement options the more important the inherent advantages of four becomes.