Just out of curiosity, what 'fan games'/'amateur games' are you refering to? I've played many fan games that give me that feeling of playing classic LA games for the first time ("5 Days a Stranger" and it's sequel are two in particular) and I've found that I've thoroughly enjoyed some amateur adventure games much more than recent commercial games...
Admittedly there are some games that completely ruin the spirit of the games they're paying homage to (I've played some dreadful Monkey Island tributes), but occasionally there are some well made games that can actually improve upon the story. I had a great time playing "M:I-2, LeChuck's Revenge", and loved the way that it filled in some of the gaps in the plot as well as creating a very clever parody of Mission Impossible, not to meantion the ludicrous multiple ending (got to love the Scooby Doo and the Seinfeld Ending)... Also, one of my favourite amateur adventure games is Cirque De Zale, which plays a biting satire towards typical adventure cliches with witty dialogue and some great humour.
I think you may have a rather stereotyped view of what amateur and fan adventures are really like. Admittedly there are quite a few bad games, but don't let it shallow your view of the many great amateur games available.
I'd recommend that you check out some more games and you might just be impressed. Just because the graphics may have a 'retro' feel to them doesn't mean they're bad. Just imagine that your playing an original Lucas Art's game again for the first time, and don't let your predudice against fan games get in the way...
