Well, everybody knows that. Right?
Of course, it's not quite that simple. (What is?) Like almost any controversial issue, people on both 'sides' of the debate are spending a good part of their time lying and exaggerating. I don't want to talk about what idiots anyone else is, so let's boil this down to something really simple.
Did you LIKE the game?
Would you like to see MORE games like that game?
Then BUY the bloody thing.
Tons of great games go unnoticed. Companies rise and fall. Whoever made that game may be struggling to keep their head above water. Unless you've done a lot of research, you probably don't know. (You may not even know who did make the game - it's not always the name on the box!)
Like a company? Think their games are cool? Want to see them make more games? BUY THE GAMES.