Sure there are timezone differences, but EST is doable for Europe. 08:00 EST = 13:00 UTC, so working 8h in EST means 13:00-15:00 -> 21:00-23:00 in European timezones. Some people may even prefer it. Europe has a larger population of devs that's underutilized because it's dispersed among multiple countries. India is too shifted for America but doable for Europe, so the natural next step is to move work completely into a much larger European-Indian worker pool that can remotely work together.
I don't expect it to happen very fast, first part this decade, second next decade. First part is going to fully equalize dev wages between Europe and America. Second part between Europe and India.
Alternatively I may underestimate the willingness of Indian devs to live a nocturnal lifestyle for a high enough pay. In which case the global equalization of dev wages with India is going to happen during this decade.