For a project like this I would say pretty unlikely because the API is already free for anyone to implement and competing implementations already exist.

The main difficulty with a system like this is the subtlety of operating it at scale with consistent performance and global availability.

The software itself only accounts for a small portion of that.

If AWS and friends were to pick this up and offer it then they would be putting in all of that work too so there would be a lot less they get for "free" comparatively (unless they offer an inferior product). i.e it's a substantially different situation from MongoDB, etc where the software is 99% of the product.