I wonder if that's because those are two different questions. Who's the most influential guitarist vs. who's the better guitarist.

Exactly right.
Hendrix was innovative. SRV polished it.

Santana will be remembered for injecting rock into the salsa. There are now thousands of latin rock bands who gladly pay homage to Carlos. He'll be remembered for writing distinctive melodies..like Samba Pa Ti. Movie makers will always seek out pieces like that for their sound tracks. Like Bing's cover of White Christmas and Nessun Dorma, great pieces of music will stand the test of time.

Anybody who's into the blues will find Robert Johnson and probably Clapton's readings of his style... which will lead them to Cream, his association with George Harrison and...the Beatles.

Surprised nobody has mentioned Brian Wilson. The Beatles recognized his tormented genius. Just as Chris Thile bored me stiff with 2 hours of solo Bach mandolin, movie makers, singers, songwriters will keep the creations of great writers alive. (Aside: I'll still go see Thile play with others, just not another infernal 2 hr of scales.)