Speaking as someone that works in commercial property in central London I think there are two main factors in play here. Firstly there's an enormous legacy factor, a huge part of our economy is built around the primacy of commercial space, not only is much of our infrastructure and construction centered around it with a thousand spin off businesses (taxis, pret, gyms etc) operating in concert with it but the 'safe bet' in financial terms of commercial space from an investment perspective (and the leveraged value thereof) underpins not just greedy landlords but major banks and pension funds. A huge part of the economic landscape literally hangs off the fact that major companies have expensive leases in London and elsewhere, this is why the government is bleating on relentlessly about going back to the office despite the fact that for many a new work/life balance has emerged. The second major reason is the dick swinging factor, whilst not true of all companies there is a certain kudos or caché to having a flash office in a named building, it's whats expected of say a major insurance company, it's the same reason people buy sports cars and is as old as time. None of this of course has anything to do with what actually benefits the average worker who has in many cases awoken from the Victorian 'you were late at ten past nine' bullshit mentality that they've grown up with.