Tom Anderson wrote:

I think this not insubstantial - there are six bus routes serving
Finchley Road, i believe.

They also serve Swiss Cottage, which has disused Met platforms, and
entrances at northbound and southbound bus stops.

There are three at West Hampstead, and the
overlap with Finchley Road's routes is minimal, so unless many routes
were rearranged, the journeys possible via Finchley Road would be
lost. Finchley Road also has the hugemongous O2 leisure/shopping
centre (and a big Homebase),

The Homebase is nearer to West Hampstead than to Finchley Rd.

and is generally rather more of a high
street than West Hampstead.

I don't agree. Finchley Road is all poundstretchers and a strip club,
whereas West Hampstead is bars and restaurants. West Hampstead certainly has
more pedestrians than Finchley Rd at night, and possibly in the day too.