You should worry they'll increase the price and worry they'll delete your data if you don't pay the higher price. It's not necessary to worry they'll go out of business just because they are charging a fixed price. They'll raise the price long before going out of business.
Having your own NAS in the mix more and more is unavoidable.
On one side, the cloud is someone else's computer they will always charge more an more for it because customers have not learned the economics of cloud hosting and how profitable it is on the other end.
On the other side, a NAS is your storage computer, in a simplified home appliance form. Connect it to back up to any cloud you wish.