Meta in particular absolutely despises using third party anything.

Having worked there for several years, I noticed early on (and kept seeing it reinforced) that they suffer from "Not Invented Here" Syndrome.

They avoid hiring third party consultants (not individual contingent workers but companies to provide services) unless those services are far outside their core business. They'll hire a media company, or an outside security contractor, or a robotics safety consultancy, but they get weird about outside engineering - often to their own detriment (just because you have some of the best engineers in the world doesn't mean they're the best at a particular discipline - so they struggle with things that they're not *actually* the experts on).

They're fearful of any dependency on outside companies - they've tried multiple times to build game engines in-house so they could break the dependency on Unity3D in particular. Facebook Games used to be almost entirely Unity3D - the push to "Facebook Instant Games" being HTML5 was heavily motivated by reducing that dependency. Same with XR. They fear what could happen if Unity collapsed, was acquired by a competitor, or otherwise became adversarial. It's a pervasive concern.

They know how important AI is - they've done foundational work in it for years - and they've routinely open-sourced or otherwise published generously licensed code because there's no negative impact for them to do so. They need the product, they need to be able to hire people who know how to work with and develop on the product, and if that means they can hire people who already KNOW PyTorch, or llama-cpp, or have experience building with Llama-3.x, that lets them skip a difficult and time-consuming onboarding process. Nothing about that tech undermines their core business (which is leveraging the power of personal connections to place advertising.) Don't expect them to release open source or open weight models that make ad placement decisions or timeline recommendations. But Generative Music Production? LLMs?

It increases mindshare, gives them the power to shape the direction of an entire industry, AND diminishes the offerings of potential competitors.

It also has a bit of a "halo effect" and helps ensure that talented and motivated engineers are interested in working for them.

Microsoft doesn't want to be too dependent on OpenAI

I won't say as much about them, but it doesn't harm Microsoft AT ALL for everyone to have access to Phi-# or whatever, and they're so much bigger than "an AI company". They're going to continue to develop their own AI solutions because they don't yet own OpenAI outright and can't let themselves be too locked in to OpenAI solutions. Many of the arguments around attracting talent are the same for them as for Meta or elsewhere. I haven't worked for them, but they also seem to have a least a little bit of the Not Invented Here thing going on, but I don't think it's as strong as it is for Meta.

For them, as a cloud provider, they really want people to independently develop using their models, and then come straight to Azure for cloud services because they're all set up for it and ready to go.