On the contrary - I think it is MASSIVELY healthy for clubs outside the top division to be drawing huge crowds. It means those clubs can generate good revenue, away from the crutch of top-league TV money.
The football league is littered with big historical clubs - Leeds, Preston, Sunderland, - all with attendances...
Sadly (in my opinion), they have been ousted by less traditional teams (Brighton, Bournemouth, Brentford) and there seems little chance of this changing any time soon.
:shrug: