I think you're vastly underestimating the amount of effort involved in getting something done by someone locally to someone remote.
Time zone is the first hurdle. Although, in my opinion, this can still be overcome in a relative short period of time.
The second hurdle is familiarity with work culture and style. For a person who's worked already in your office, knows the system, knows all the procedures, knows the nooks an crannies of how all the softwares behave, who to call in case of issues, how to resolve them. All these aspects add to a significant amount of non-quantifiable knowledge which lots of organizations don't consider while outsourcing initially.
The third is process. Most organizations have their processes worked out over time. And this is rarely, if ever, documented. Even for people coming to office, there's a certain amount of time till they get familiar with this.
However, the biggest challenge is communication. This means everything - grammar, vocabulary, diction, accent, familiarity with jargon, parts of speech, colloquialisms, everything. To make a requirement understood itself is a challenge. Asking questions about that requirement when faced with a roadblock, is again a bottleneck.
As an Indian, who's worked in most of the English speaking countries, and now working from India, I can just humbly say this - never outsource to cut costs. This will bite you hard in the short run. Only if you have processes set, softwares used correctly, procedures documented, should you look into outsourcing. And that too it should be for reasons other than purely financial. As an example, having remote workers across time zones helps in maintaining support for your global customers better. Similarly, time zone differences can be used to your advantage. Finally, interacting with different cultures can only improve your organization's awareness, maturity, communication and global reach.