Doesn't selling other items to get a bag also help Hermes sell "hard to sell" items (dinnerware etc)? I don't think they have much sample sales or events to get rid of outdated inventory.
There could be an incidental benefit to widening the sales spectrum, but I doubt it was the primary reason for the wider purchase base situation.
Hermes does have sales in Paris but they are not known about widely
and only accessible to the people who can be there over a very limited time.
If you read about the lead time in getting items like table-ware, it would appear the Hermes has more trouble meeting the demand than selling.