"Shell" apartments

Bad idea...

I lived in Thailand for a while where this was common and its a shocking idea because for the people living in the building from early on have to put up with construction noise for the others who are fitting out their apartment. So many people came and went as they couldnt tolerate the noise. Concrete buildings are good at transmitting noise!
My partner is from Brazil and in many states there they have this crazy system - even for renters(!?) - of including an EMPTY kitchen in homes! Meaning, if you sign a 6-month lease you need to BYOB kitchen cupboards and benches!!

Kitchens will usually come standard with a sink and tap and that's about it!

in the less glitzy states of Brazil (which is oh I don't know.. About 90% of the population); you have gas cooking, but not via installed gas lines.. No no, people just go to the servo and rent cylinders that plug into their (self-supplied) stove!

This is just one of the reasons why many people in Brazil who rent, rarely move house. If it wasn't for the horrible beauocracy in terms of administration; I'd buy IPs in some parts of Brazil for sure.
Its quite common in many parts of the world.
Every one seems to be assuming that the developer would be the one completing it beyond a shell - but that's not how it would work. They would finish the shell and hand it over. You would need to source your own trades to complete it (or DIY).

Eg in Russia - You can also choose the level of fit out. In other words some will choose a complete shell - basically a concrete shell with nothing (not even wiring completed). Or you might get them to do wiring, piping, flooring and painting. So you just need to buy a kitchen and bathroom. Or you can have it completely finished - they will sell off the plan in a variety of 'finishes'. Often they will have glossy brochures of different colour schemes you can choose from. You pick either A) B) C) or D) scheme. Or maybe a 'show room' come Display home.

Costs are relative to each choice.

I guess in Australia our trades are so expensive and unreliable it would be hard to get the unit complete once the developer was offsite.

Also as others have mentioned the finance arrangements are different. Even off the plan the developer receives a lot of the funds upfront. More risk is taken on by the individual(s). Hence you see a lot of "mum and dads" getting screwed over.