The approach to music as an art and a heavenly endeavor was new to Beethoven’s time and Mozart simply would not think that way. No one of his time would. It was a craft to him. The word Art or Artist never occurs in Mozart’s letters. You’re projecting attitudes backwards into a time when they did not exist. Mozart was radical in his harmonic freedom but his music certainly does exhibit the core qualities of the era. Mozart would never start a symphonic work with a terse motif like the opening of Beethoven’s 5th. To Mozart that would be ugly music. A better question would be who is superior to Mozart in the 2nd half of the 18th century? You seem to have a condescending attitude to the music of that time.
NOW you're starting to ask useful questions. And there you might have me. Mozart had few equals during that period, the most likely being Haydn. If you had specified the early half of the century, I might have defended Vivaldi as a challenger, although I would have trouble arguing that he was superior, if indeed even an equal. I also personally like Albinoni and Teleman from that period, but the same caveat applies to them. And Wagner came a little too late to qualify. CPE Bach did some good work during that time, but not of the caliber of Mozart. As did Boccherini, if you like a carryover from the more Baroque period. Even Antonio Salieri produced some notable opi in that time. But I will concede that, limited to the period you describe, Mozart was the luminary.
You seem to have a condescending attitude to the music of that time.
Nonsense. I have great respect for Haydn, and I delight in Mozart. My objection is to the assertion that the latter was the superior of Ludwig Van Beethoven. That is one step short of sacrilege in my book.
Beethoven wrote the music angels whistle on their way to work, and God Himself hums in the shower.