I see this a lot. Everyone expects a rock star who knows their entire stack. If you don't know their stack to the nth degree you are classified a junior and get paid 30-45k which is a joke in London. People like myself end up self-employed earning multiples whilst hearing on each job, "would you go perm for xyz?" (that boat has usually sailed).

The reality is companies need to get the right people in. Send them on courses, get them involved and pay them properly. Use contractors to fill the gap, pay the high rates then remove them when 'the right people' are ready (and/or offer contractors an appropriate compensation to go perm)

[edit] I think the London market is way out of wack. I've had offers to go perm at the equiv of 3~ months freelance pay, it just doesn't make even remote sense. Even more so when uncertainty is rife.