They were also 100% cost driven and not value driven. A lot of companies have opened offices in other countries and hired great people, but they focused exclusively on value.
Most companies just looked at the direct cost and went with it. Of course they picked the absolute worst workers and so the whole scheme collapsed.
I would definitely argue a loss of productivity. But those costs are far outweighed by the benefits, such as less overhead, greater hiring radius, and flexibility. Plus a lot of the weaknesses are more managerial than technical, like synchronous vs async tasks and finding more effective ways to measure productivity.
Once you decide to go to "Europe" then the question becomes why the UK and not somewhere vastly cheaper like Romania or Poland. Wages in the UK are lower but wages in eastern Europe are much lower still.
Not as true now as it was even 2 years ago. Slovakian wages are reaching parity with the "West" of Europe, and Romania is climbing as well.
Until the war, Ukraine was also climbing that same ladder. And when the war is over, they will soar. Their skills are at least the equivalent of any developer I've worked with, their language skills are impressive, and their analysis and design skills are as well.