Because today they're racing against regulators for the privilege of setting their own service as the preinstalled, exclusive, default with APIs only they are allowed to use.

They already lost this superpower in the EU and I think Japan, India, Brazil too. Early next year they've got their US antitrust trial, and later in the year are some class actions challenging their control over app distribution, and at least two pieces of draft legislation are circulating that would require allowing competing apps to be defaults.

If they need another two years they might face an entrenched and perhaps even better competitor, while their own app needs to be downloaded from the App Store.