It’s a tragedy of the commons problem. Most of the money available is not tied up to decision makers who are ideologically aligned with open source, so I don’t see why they’d donate any more in the future.
They usually do so because they are critically reliant on a library that’s going to die, think it’s good PR, makes engineers happy(don’t think they care about that anymore), or they think they can gain control of some aspect of industry(looking at you futurewei and the corporate workers of the Rust project)