I don't know. I've actually seen some pretty impressive stuff out there. Courtyard by Marriott started providing Paul Mitchell shampoo and conditioner. One time at a Hilton I saw Peter Thomas Roth, which is generally pretty pricey. However, they might have been packaged by some third party under license. Caesars (formerly Harrah's) seems to be supplied by some company called Gilchrist & Soames. I've stayed at a variety of their properties, and the toiletries have different labels depending on the brand name of the hotel - even names like Rio or Paris where they don't have multiple hotels with that name.
One of the more interesting things I remember was cotton balls at a hotel I stayed in after a company party. The party was at the hotel, so I figured it would be a good idea to sober up there. My kid went nuts playing with the cotton balls. Their toiletries were L'Occitane de Provence.
Once we stayed at a Four Seasons hotel in China, and my wife hasn't been the same since. However, they had toiletries from some Italian perfumer name Lorenzo Villoresi. It was perhaps the best service I've ever seen at a hotel. We arrived with our kid, and while we were checking in they gave my kid a stuffed panda toy with the Four Seasons logo on it. After we arrived in the room, housekeeping came by with children's toiletries, a kiddie cup, and toothbrush/toothpaste. And the cost (with breakfast) was less than a night in Manhattan.