Attack of the clones

Being a casual games addict, I keep discovering & playing lot of "new" games on the web. I generally prefer to play free online versions than downloading. I must have seen 1000+ games, played over 300+ games so far and I regularly play around 30-40 games. Most of these games fall in the category of puzzles and arcades which are always addicting and has got the most repeat value. But I am surprised to see 1000s of clones of some of the popular casual games like Zume, Bejeweled, text twist etc.
AT last count, I must have come across 100 clones of Bejeweled, 50 clones of Zuma and 100s of clones of Text Twist.
I was wondering why casual games developer take that route - may be to encash on the popularity of such games or there is lack of creativity and good analyticals mind in the industry. Even big publishers games like Zuma and Luxor are clones. Well I am not against clones because it stops developers/publishers from boasting too much about their skills and extracting more money from the users.
So let me know your views on the clones???

- Deepak Abbot