At first glance, it can be discouraging to new VAs entering the field. But there is light at the end of the tunnel. I have been seeing more and more RFPs where native English is required. Some PCs have also told me that they started out with offshore VAs and were not happy with the results and decided not to repeat that again.
Not even getting into the quality of work that offshore VAs produce, there are many other differences that come into play, as already mentioned. Such as: cultural differences, time zones and different holidays. These all big factors that may work for some clients but not all. Maybe some clients can work around these differences, preferring to pay the lower rate especially if they are just starting out. But as their business starts to make money, they are able to afford a professional VA that is closer to home.
I just had this experience with a PC, emails were sent back and forth and at the end the PC told me that they were a startup company and gave me two rates they received from offshore VAs and I couldn't beat their rates. I wished him good luck, and he said he would be contacting me in the future for "more professional services" but right now he couldn't afford it!
Also, many clients just want the luxury of picking up the phone when there is an emergency situation. This cannot be done if the VA is halfway across the globe, sleeping!