If you're using Beethoven as a standard of comparison, don't be surprised if every other composer who ever lived comes up somewhat short. Of course, that would limit the number of truly great composers in history to exactly one, which is a reductio ad absurdum of using Beethoven as your standard-bearer.
In favour of Tchaikovsky, can you name any other composer who has contributed so much in so many different areas?
Tchaikovsky is, in many people's opinion, the greatest composer of ballet. Stravinsky is his only serious rival, in my opinion. On the other hand, Tchaikovsky also contributed superb examples of the following genres:
Operas - certainly Eugene Onegin and The Queen of Spades, but Mazeppa and the opera about the Czarina's slippers (the title escapes me) are all wonderful.
Symphonies - certainly the last three, but all of them except #2 are very good pieces.
Concertos - the First Piano Concerto and the Violin Concerto are war-horses in the best sense of the term.
Other orchestral music - Romeo and Juliet, Francesca da Rimini, Hamlet, Capriccio Italien, the Orchestral Suites...
Chamber Music - the first string quartet, the aforementioned Piano Trio, the Souvenir de Florence...
I'm omitting his solo piano music and his songs, mostly because I haven't heard a quarter of them, and though worthwhile, he was no Chopin or Schubert.