It would probably depend on how you count it.
If you look at the catalogue you have separate entries for:
Marines blister
Marine boxed set
Marine with plasma gun
Marine with melta gun
Marine with flamer
Marine with heavy bolter
Marine with lascannon
Marine with missile launcher
Marine sergeant x 2 or 3
Marine with plasma cannon
Marine devastators box
Assault marine
Assault marine sgt.
Assault marine boxed set
and eventually Marine with Multi melta
And so on plus variants for each with Space Wolves and some for Dark Angels and Blood Angels.
Now you have
Space Marines boxed set
Assault Marines boxed set
Devastators boxed set
plus variants for blood angels, space wolves and dark angels.
So you have eliminated a lot of SKUs without getting rid of any actual model types. You can build all of the above with those three boxed sets.
The same was done with most races.
They have eliminated a lot of specialist games stuff to refocus on 40K and AoS.
But they have added a number of new factions and greatly expanded the rest.
Instead of just Grey Knight Terminators in packs of two you now have a whole Grey Knight army.
Every army has flyers and many have large tanks or robots.
So they may have a lot fewer codes, but the core games have a lot more options than they used to.
I would imagine this is a huge plus for independent retailers. It means that you can carry the whole range of things without having to guess ratios for what people want.
I remember wanting to buy a unit of something or other and not buying anything because they only had a blister pack or two of what I wanted and I needed 5 or them having the right number of figures but not the right combination.
Now I just buy a box. Easy-peasy.
So you are probably right. They probably do have about half the SKUs that they used to have but the codes they have provide retailers with more variety in a single purchase and allow the customer to get what they want in one place.
Having it all that way now, bringing back ALL of the old codes at once would probably be pretty unmanageable. If they are going to bring them back in lead the casting and storage of the molds, figures and so forth might not be something they have the space for. You might bring so many old molds from the storage facility at a time, cast them up until the demand runs out and then take them back and bring the next lot out.
Makes sense to me.