The whole POINT is to have all b-sides and rare tracks collected in expanded editions of the albums.
What sold the most is irrelevant!

The other thing to remember is a physical release is very unlikely these days, especially if it would be more than 2 CDs worth of music. The 2015 Expanded 'The Day Is My Enemy' CD was only sold via the online Prodigy store and it had less tracks than the digital release. A remastered, digital version of the rarer tracks would be the most likely to happen (in an already unlikely scenario). Like I said, it would be nice just to have the Vinyl only, promo only, etc tracks available on music streaming services and available to buy as FLAC/WAV/MP3/etc.

The announced 'The Fat Of The Land 25th Anniversary Edition' is unfortunately another example of missing the opportunity to release an Expanded version with rare, instrumental, unreleased, remixed, not on streaming sites, etc tracks. In these days of Digital releases it could surely still be possible to release a Digital Expanded version of the album by November the 4th made up of the following tracks (not even counting tracks we don't even know about).

'Diesel Power (Dirtchamber Remix)' (Only available on 'Against The Grain' promo)
'Mindfields (Monkey Mafia Mix)' (Only available on 'Fresh Packed Cuts' promo)
'Breathe (Instrumental)' (only available on the 'Breathe' 12" Vinyl single)
'Firestarter/Smack My Bitch Up' Mashup (from the BBC Maida Vale live set for BBC Radio 1)
Unreleased Instrumentals of the vocal tracks 'Diesel Power', 'Serial Thrilla', 'Mindfields', 'Narayan' and 'Fuel My Fire'.

'Smack My Bitch Up (Jonny L Remix)' (Only available on '1997: The Tunes' Muzik Magazine CD)
'Smack My Bitch Up (Slacker's Bass Bug Mix)' (Not officially released)
'Smack My Bitch Up (TC Remix)' (Not officially released)
'Funky Shit (Mulder Exclusive Mix)' (Only available on 'Aphrodite & Micky Finn – The Takeover Bid')

'Firestarter (Andy C Remix)'
'Breathe (feat. RZA) [Liam H & Rene LaVice Re-Amp]'
'Breathe (feat. RZA) [Liam H & Rene LaVice Re-Amp Instrumental]'
'Breathe (feat. RZA) [Rene LaVice Dark D&B Remix]'

'Firestarter (Instrumental)'
'Firestarter (Empirion Mix)'
'Molotov Bitch'
'The Trick'
'No Man Army'
'Smack My Bitch Up (DJ Hype Remix)'
'Mindfields (Headrock Dub)'
'One Man Army' (Only available on 'Spawn' soundtrack)
'Smack My Bitch Up (Sub Focus Remix)'

'Smack My Bitch Up (Noisia Remix)'
'Firestarter (Alvin Risk Remix)'
'Breathe (Zeds Dead Remix)
'Mindfields (Baauer Remix)'
'Breathe (The Glitch Mob Remix)'
'Smack My Bitch Up (Major Lazer Remix)'

i dont get it...why liam is so lazy in this kind of things

perhaps he is unhappy with released half baked ideas, ever considered that?

Liam may not want to release unreleased tracks but an expanded version of 'TFOTL' with previously released 'rare' tracks (only available on Promos, vinyl only, etc) as per my list would please most fans.

I asked Liam's manager Nick Halkes about the possibility of them doing an Expanded 'The Fat of the Land' including the tracks off the promos, instrumentals, etc. He said "Always aware that there's fan demand for rarities. Not always possible to meet it for multiple reasons."

It sounds like music copyright ownership/licencing/etc are some of the reasons why these tracks don't get released. That's a real shame.

Just as a quick example on licencing, why are the BBC Maida Vale live set tracks 'Poison' and 'Voodoo People' on the CD of 'More Music for the Jilted Generation' but not on the streaming version of the album? It makes no sense to me but I've noticed a lot of BBC sessions by other artists also aren't on the streaming sites. If the BBC (or whoever) own the rights why don't they do something with them?

Tracks/singles/EPs/etc also come and go on the streaming websites, e.g. the 'Hotride' and 'Everybody in the Place' EPs.

They may have the rights for the recording, but not necessarily publisher, writer and performer rights. They would all have to agree to make it work. On physical media it may be easier to agree on a flat rate fee compared to streaming? Just speculating.

On spotify, the Firestarter Empirion remix and the instrumental versions are still swapped, and have been for the last 10 years. It all just seems like a mess.

Thank goodness for physical copies

Yes, we don't know the legal complications involved in music publishing. Unfortunately it's a lot more complicated than we imagine to release a track, especially if multiple parties have an interest in it.

The only thing I really really want, is an expanded AONO:

AONO Disc 2:
1. No Souvenirs (1st mix)
2. Baby's got a temper (1st mix)
3. Trigger
4. Nuclear (1st mix)
5. Frequencies
6. Heatwave Hurricane
7. Back 2 skool (1st mix)
8. Good morning (feat. Juliette Lewis)
9. Dust yo self
10. Benny Blanco
11. Little Goblin
12. Hotride (the live remix)
13. Wake the fuck up (the live remix)
14. Get up get off (alternate)
15. Gun reprise
16. Night boat to Cairo
---- another bonus tracks
17. No souvernirs (2nd mix)
18. The gun
19. Nuclear (2nd mix)
20. Ice (demo)
21. No souvenirs (3rd mix)