Yep....this is the reason why I always pre-order on day one with Amazon Prime....pre-order price guarantee. There's really no downside if you don't want to wait months for a sale or further price drops.
Yeah, I've kept my Amazon pre-order too. I ran the Shout offer through my cart, with shipping my total was $86.48, so I'm hoping the Amazon price drops into that area before release.
Just FYI....Shout is currently offering the set for $79.99 with deliver 2 weeks before street date....
https://www.shoutfactory.com/film/film-comedy/the-pink-panther-film-collection-starring-peter-sellers