I doubt that was the case. Looking at HL2 now, with all those other FPS games that built up upon what HL2 introduced, of course it doesn't look that impressive. But at the time, it felt like it came from the future. The whole physics gameplay aspect was pretty much unprecedented at that time, especially with how seamless and integral it felt. It didn't feel forced or bolted-on at all.

A good analogy in other media would be Citizen Kane (movies), NWA (music), or Akira (japanese animation). Neither of those would garner mass praise if they were released today, but they were first of a kind and paved the way for moving their respective medium forward.