Had Beethoven been able to carry out all his plans to fruition, then, for example, today we would have his opera Macbeth, a Faust, and many others. He would have contracted himself to write a whole series of operas.
But, on the other hand, if Schubert were alive today, he would find even richer fields to plow.
The reason why Schubert is celebrated so much today, lies rather in the fact that there has been nobody else like him - not before him, not after him.