That doesn't seem like it would work. Isn't it basic supply and demand dynamics? If people can work remotely in London from their home elsewhere the supply of available Devs for London companies has increased. They don't need to offer the same full salary any more because they'll have lots of choice to offer less, or give it to someone else.
You can't just avoid supply & demand dynamics by saying everyone should just hold out until they get a higher offer. As a non-London dev myself I can tell you I'd snap up a remote job for a 20% payrise, and I suspect most would. Your suggestion of only taking the full on site salary only works if everyone does it, and most will take lower. It's a prisoners dilemma kind of problem, if we all agreed to hold out for higher salaries we would all benefit, but for each individual it makes sense to defect and take lower because if you don't, someone else almost certainly will. The salary will reach an equilibrium where supply at that price matches demand.
Also, no offense intended about the numbers ;-). I mostly just made those numbers up with no bearing on reality. I'm actually more northern myself, and I'd say average senior dev salary here is probably around £50-60k. I don't really have any idea about equivalent London salaries.
You can't just avoid supply & demand dynamics by saying everyone should just hold out until they get a higher offer. As a non-London dev myself I can tell you I'd snap up a remote job for a 20% payrise, and I suspect most would. Your suggestion of only taking the full on site salary only works if everyone does it, and most will take lower. It's a prisoners dilemma kind of problem, if we all agreed to hold out for higher salaries we would all benefit, but for each individual it makes sense to defect and take lower because if you don't, someone else almost certainly will. The salary will reach an equilibrium where supply at that price matches demand.
Also, no offense intended about the numbers ;-). I mostly just made those numbers up with no bearing on reality. I'm actually more northern myself, and I'd say average senior dev salary here is probably around £50-60k. I don't really have any idea about equivalent London salaries.