iPad Pro, what if a new one comes out?

There's always going to be a new one. Apple sells iPads, and they are always releasing new ones. At least once a year. Or are you expecting your iPad to be the last new one they ever produce until you decide its time to upgrade?

Apple has no direct way to upgrade to a newer one when its released (not for free anyway). Nor any reason anyone should expect such a thing.

You can trade yours in, and get credit for it which can be used towards the purchase of another device, but it still going to cost you the difference.

Read here

iPad Trade-up - Apple

What people normally do, is sell their old iPad privately and use the money to buy a new one. You cannot have the newest one forever.

It's best to just buy what you need when you need it, and not worry about whether Apple releases a new one, because they always will at some point release something newer that what you bought.

Apple is continuously working on new models of all their devices. A new model of every device is inevitable (well, other than the Mac Mini sadly). Just because a new model comes out, that does not mean that your current one will not continue to meet your needs for a long while. There are posters on these forums still using their original model iPads.

As long as your device does what you need and want, then what difference does it make if a new model comes out? Almost all computing technology is technically obsolete within 6 to 12 months of hitting store shelves. Technically obsolete (i.e. displaced by an updated model) does not equal useless or un-usable.