Because of this:
https://fr.wikipedia.org/wiki/Bic_(entreprise)
Up to this day many still say, on a daily basis, say, a "bic bleu" (blue ballpen) or "bic noir" (black ballpen).
And virtually everyone french speaking calls a refrigerator (fridge) a "frigo".
* Cornstarch is called maizena
* Adhesive bandages are called bandaid
* Instant noodles are called miojo
* Yogurt sold in small pots are called danone
* Chewing gum is called chiclete (from Chiclets)
* Photocopies are xerox
* Bouillion is knorr
* Glass plates are pyrex
* Scooters are lambretta
* Soluble cofee is nescafe
* Sunglasses are rayban
And same goes for teflon, jacuzzi, velcro, tupperware, vaseline, botox, googling, ...etc, etc
When I was a kid in Brazil everyone called all scooters Lambrettas, even though none of them were Lambrettas. They usually were... Vespas.
Now that I know it is actually rivalling companies, I wonder how sad Lambretta and Vespa companies are, with eveyrone calling their Vespa a Lambretta.