Because the larger the sensor, the greater the field of view for a given focal length.That's why I don't read other people's theoretical articles. I test for myself.
If it didn't make any difference, then why all these insane debates about why FourThirds format doesn't give you the ability to make shallow depth of field, why FF lets you get beautiful bokeh, why MFD gives you such shallow and controllable DoF, etc etc?
The only thing that has a bearing on perspective is absolute subject distance.
Therefore, for a given subject distance and desired framing, the larger format enables you to use a longer focal length lens.
Longer focal length, same subject distance, shallower depth of field.
At least, that's the way I've always looked at it.
Kind regards,
Gerald