Yeah this is the reason most offshoring projects ultimately fail to deliver the promised savings. The overseas staff can never be as effective as folks in the same time zone.
Offshoring is valuable not to save money but to increase the development and operational bandwidth of the organization. This truth may not be known to the decision makers, but it is clear to the workers over time. It does increase the cost of coordination and the difficulty of establishing a common technical vision, but these are mitigatable by for example sending entire software project to one region, with the colocated workers having a higher degree of autonomy to make decisions. One way of partitioning work that fits with the power dynamics is to have all the new shiny things done in North America and mature profitable software is owned by a remote region. Half smiley but this effect is real.