A big company that's resisted remote working will find it hard to integrate remote people in to their teams. Remote is great, but unless everyone is in favor of it it can fail horribly - a manager who insists on having oversight of what people are doing at any given moment will kill any chance of remote workers being productive. Consequently if you have a big team at 'head office' who aren't used to or good at managing remote people then remote won't work.

Paying people to relocate from a small city to the most expensive place in the country is exceptionally difficult and expensive. Many developers here in the UK see London as a really bad place to live unless you're paid more than £100,000. Developer wages in London are often not £100,000.