They are updating it later this year. But for the past maybe 5 years Apple has been using legacy text messaging tech for normal, standard, phone-to-phone texts. Because Apple also has a proprietary messaging app (iMessage), texting from one apple device to another didn't use the texting protocol.

The legacy tech didn't allow you to send large images, videos, see read receipts, see typing indicators, leave groups, have large groups, etc., etc.

The update will fix most of that. IMessage will still have features you don't get when messaging non-apple devices. And people suspect Apple will find a way/excuse to continue to make basic messaging worse than it needs to be.