As a massive Disney fan, the parks would be very different! Almost all new rides in the parks are based on Pixar / Marvel / Fox properties.
Firstly Pixar - The Pixar brand pretty much turned around the failing 'California Adventure' after the 'Pixar Pier' conversion. Toy Story alone has more rides than any other movie with Midway Mania, Slinky Dog Dash, RC Racer, Toy Soldiers Parachutes and Slinky Dog Zig-Zag Spin. The French pavilion in Epcot is getting Remy’s Ratatouille Adventure (which is already in Paris). There would be no crush coaster, no Radiator Springs Racers...
Disney probably wouldn't have entire areas of their park dedicated to Pandora and Star Wars, both of which were after the aquisitions of Fox (Avatar) and Lucasfilm (Star wars). Both Florida and California have Guardians of the Galaxy rides enabled by the acquisition of Marvel, and are planning more Marvel based attractions.
Bob Iger realised that just licencing these properties wasn't good enough - only ownership of the brand can protect Disney's long term interests ('What if pixar decides just to stop making Toy Story? Or refuses to licence their next hot property? Or gets acquired by our competitor?').
Name one decent Disney animated movie that was released after Pixar was founded (excluding Pixar films post-acquisition).
There aren’t many because most of Disney’s talent left around when Pixar was founded. Without movies to continuously hook new kids, their entire empire is a house of cards.
Pixar was founded in 1986. They started releasing theatrical films with Toy Story in 1995. Are you really saying there hasn't been a single good Disney animated movie in the past 25 years? What's the basis for that statement?
The history of the two studios is way more involved than what you're suggesting, and talent moves around between studios quite a lot. And 25 years is a long time; there have been entire generations of talent that have risen up since then, and trust me, they're not all at Pixar.
Source: I worked at Disney Animation for nearly a decade (and closely with Pixar during that time). I'm certainly not unbiased but probably way more informed.
The argument is that HBR's article is just speculation, nothing more.
Some mergers have literally saved companies, some have ruined them, some are considered 'unsuccessful' for esoteric reasons and others successful for purely numeric ones.
