This is factually wrong. The only barrier isn't 'time zones' and will never be just time zones. It's cultural, environmental, political. The way a US-based team builds a product is different from an outsourced team in India which is different from having an actual office and team in India. Trying to get a team in a whole 'nother part of the world operate on a US time scale is incredibly hard because they are going to have different holidays and time off. You may need a product delivered this week, but your key developer in Ireland is off for a week and they have the federal right to do so.
In the United States we have -zero- mandatory minimum paid vacation or holidays. Your employer could require you to come in and work to push a product out. You cannot do that in most other countries.
Like with these kind of remarks I start to wonder how seriously you're aware of with countries and holidays outside of the US.
Can it be a bit of both? Trying to get a everyone to pull in the same direction when more than half of them are in another time zone is such an uphill battle. Even smaller things like trying to resolve CR feedback in a reasonable amount of time becomes a herculean effort when you only overlap for about an hour each day, and all other communication falls into a "We'll see what they say tomorrow" bucket.
Returning to a team that was all (more or less) in the same time zone has been amazing for my sanity.
In the United States we have -zero- mandatory minimum paid vacation or holidays. Your employer could require you to come in and work to push a product out. You cannot do that in most other countries.
Like with these kind of remarks I start to wonder how seriously you're aware of with countries and holidays outside of the US.