Since the above comment was deleted, here's what I was replying to for anyone wondering:

That all sure sounds awfully successful and self-sufficient and "we're a strong independent nation, we don't need no big dumb international union", golly. And yet, here we are talking about the UK asking very nicely for things they had before and rejected.

No, it says that the success/failure of the UK financial services sector is irrelevant to any discussion about the EU and the pros/cons of membership for the UK.

If you look at the wider economic cost/benefit analysis it's clear as day as to the advantages we had of remaining part of the EU and that could be somewhat clawed back by rejoining the customs union.

For example:

https://obr.uk/forecasts-in-depth/the-economy-forecast/brexit-analysis/#assumptions

The post-Brexit trading relationship between the UK and EU [...] will reduce long-run productivity by 4 per cent relative to remaining in the EU.

Both exports and imports will be around 15 per cent lower in the long run than if the UK had remained in the EU.

New trade deals with non-EU countries will not have a material impact, and any effect will be gradual

Or:

https://www.nber.org/papers/w34459

estimates suggest that by 2025, Brexit had reduced UK GDP by 6% to 8%

We estimate that investment was reduced by between 12% and 18%, employment by 3% to 4% and productivity by 3% to 4%

these forecasts were accurate over a 5-year horizon, but they underestimated the impact over a decade