Preface: I'm in the Unites States... I dislike and do not use any crowdsourcing site to acquire new work or clients.
To answer why rates seem low on some crowdsourcing sites.... Exchange rates
$10 in the United States is equivalent to ...
- 726 Indian Rupees
- 156 Egyptian pounds
- 1,090 Japanese Yen
- 65 Chinese Yuan
- 143,619 Indonesian Rupiah
Rates may be low to you based upon your local currency. However, rates may be much, much higher than average pay rates in another country. Many workers in these countries can afford to drop to an equivalent of $1 US... while most workers living somewhere with a strong currency (US/UK/CA) can't afford to work for $1/hr or £1/hr.
If you are attempting to compare what others completing similar projects are charging, you need to only compare rates for others using your same currency or where an exchange rate is closer to a 1:1 ratio.
This, among other things, may be why crowdsourcing sites could not be a feasible outlet for acquiring clients if you live in a country where currency is strong and exchange rates work against you. It's difficult to compete against others capable of always outbidding you due to exchange rates.
And you are right, those capable of working for exceptionally low rates due to currency exchange devalue the work for those in countries where currency is strong. There's not much one can do about it though. With the advent of crowdsourcing allowing members all over the world to register and work, crowdsourcing is a global market/workforce - helping those in some countries while hurting those in others.