Europe is not a country.

Many Western European countries like the Netherlands we have seen the same pattern of the white middle classes fleeing to new suburbs whilst the old city neighborhoods got taken over by newcomers.

And it is still how things are in many cities. Whilst the city center may have been revived and gentrified and looking all lovely and touristy, the surrounding neighborhoods are often dominated by poor immigrants, whilst the original lower middle class and working class lives in the suburbs.

The only options in the city for the ordinary "white" families are neighborhoods they can't afford and neighborhoods they don't want to live in. Sounds familiar?

It might still happen for a variety of reasons. I live in London, and not all boroughs/districts are equal. Compare posh Kensington on the western edge of the London Underground Zone 1 with Whitechapel and Hackney at the eastern edge and you'll see a massive difference. Interestingly both areas are seeing a huge increase in ethnic diversity, but in Kensington it's the ultra-wealthy.

Who would the white Europeans be running away from?

No one, which I believe is his point?

Nowdays they might flee from muslim immigrants, just suppose.

Yes, but they mostly live in the suburbs of cities like Paris, while the inner city remains affluent and white. Do Europeans just do a more effective job of keeping poor people and ethnic minorities from moving into the inner cities in the first place?

A lot of continental inner-cities (Paris, most Italian towns) were already too expensive way before "immigration waves" were even possible. In that sense, newcomers never got a chance. Any town that has existed since Roman times has had two thousand years in which to solidify the link between location and social status, to a point that will likely survive anything bar catastrophic events.

The suburbs didn't exist when people started immigrating to cities like Detroit.

It's not a coincidence that curry is so popular in Britain.