If the bubble bursts why would Apple buy any AI companies?
For the same reason that Yahoo should have bought Google after the dot-com bust. AI is useful and will eventually change the world. Many companies won't be able to provide sufficient returns, but will still have useful assets that Apple could buy at a discount.
More likely they would buy the assets of AI companies for pennies on the dollar. There could be a lot of H100s floating around at fire sale prices. Or they would acquire these companies for talent.
Google did this for several years in the early 2000s – snapping up talent and data center capacity from the casualties of the dotcom bust.