I think he would be too. I’m not sure where I saw it but in some rocumentary his friend said he told him, “let’s face it, in 30 years they may be singing Yesterday, but they won’t be singing I Am the Walrus.” Or something like that. Meaning, he felt that Paul’s music (not lyrics) would be more enduring than his.
It’s not that Paul’s music is more enduring. Paul’s music is often more melodic and easy to sing. But John wrote “In My Life,” let us not forget, which one music publication called the best song of all time.