Do you think they'll release the entire game so far as a complete package for £60/100?

Or will they make us buy each individual expansion pack like they do atm?

At the moment, they do not do that and you can buy a Complete Edition already for $60. If you didn't want to fully commit you can also buy the Starter Edition for $20 which includes the base game and the first two expansions.

I do not expect that this policy would change if it comes to Xbox, except for potentially adding additional expansions to the Starter Edition as later ones are released.