Obviously his work is based on the result of others, you could make that claim for 100% of scientists and mathematicians.
Not only was relativity a mind blowing thing that he clearly saw through, there's the massive leap to general relativity, then there's the photoelectric effect, Brownian motion, the mass energy equivalence, Bose-Einstein condensate, the cosmological constant and even his work on quantum entanglement. Any of which would make a physicist very famous. For one single person to come up with so many ideas, is almost unbelievable.