Yeah, you win some, you lose some. Never said we'd keep everything / everyone.
As for UBS, HSBC etc... yeah, as above. HSBC reckons it will lose ~20% of revenue generating work from London, Credit Suisse said the same figure, but they also expect London to quickly bounce back. That's fine, and expected TBH. I don't think any Brexiteers expected there to not be a bit of painful adjusting.
Meanwhile, it's not clear that Brexit's been that bad - note this was announced the same day as the Brexit bill got royal assent:
https://order-order.com/2017/03/16/t...despitebrexit/
This was probably planned last year, perhaps even before the referendum, but if major firms are either (a) choosing to invest post-Brexit, or (b) maintaining pre-Brexit investments... eh, it doesn't look so bad for the UK economy TBH. Again, there probably will be short-term pain, as with the loss of 20% of HSBC's revenues etc, but long term we'll see the economy bounce back, and then some.