But not everybody read Raising The Bar and not everybody joins a game community. If you had just been introduced to the series with no prior familiarity, you wouldn't understand.
Well, I for one had pretty much zero memory of HL1 when I purchased HL2 some 7 years or so after the original and quickly put together the pieces at the beginning of HL2 to understand what was going on.
Yes, my initial impression was "what the heck is going on here?".... but that was the intent of Valve when they created the opening chapter of Half Life 2.
After playing through HL2, I did go back and play through the original HL again and in turn, connected more dots than I had originally made.
When I bought Episode 2, I was given copies of HL1 and EP1 to give away to friends, and the friend I gave it to had never played Half Life 1. He was immediately hooked on the game and had excellent understanding of what was going on even though he never played the original.