I'd say that it's realistically not possible for any amount of cost or complexity of compliance to make them leave the EU market.
Apple has a vested interest in being able to offer their services worldwide. If one part of the world is not included, companies in that part will have a much easier time to develop and grow their own alternatives. If these alternatives gain enough traction in that part they might then be able to threaten Apples services globally.
Therefore I'd assume that even if they will only break even (or operate at a manageable loss) they would still stay in the EU.
Apple has a vested interest in being able to offer their services worldwide. If one part of the world is not included, companies in that part will have a much easier time to develop and grow their own alternatives. If these alternatives gain enough traction in that part they might then be able to threaten Apples services globally.
Therefore I'd assume that even if they will only break even (or operate at a manageable loss) they would still stay in the EU.