Because OSS organizations just not created for this.
Next I will say about typical OSS org, not some daughter of commercial corporation like Apple, or Google, or Microsoft (or any other FAANG member, or how it called now).
So, exists huge number of just unregistered tiny OSS producers, who do it just for fun.
Some OSS producers become medium entities (mostly, non-profit), and some even large.
But they not intended to do this for money! This is just hobby, even when this hobby gives rock-star like popularity.
And as I looked on internal regulations of OSS, they usually avoid liability at any cost.
This is problem even in large commercial entities, but in non-profit this is just nightmare, nobody want to be responsible.
Fortunately for them, modern bureaucracy gives some methods to avoid DIRECT responsibility - they use Board of Directors; mimicry to Direct Democracy methods - conduct plebiscites on all important questions; and use all other tools of big businesses, to avoid direct decision making and responsibility.
Well, in past, when software was not really important, all these things was totally normal. But unfortunately, these large decentralized entities are uncontrollable, in sense, they could long time maintain way, on which they step when decentralized structure built, but for them impossible to reform this structure, to turn it to other way, to match changed environment.
And when I said, commercial entities have same issues, yes, they literally same, with just one difference - commercial usually made to make profit, but money is not just profit, they are equivalents of resources, mean, reserves, which CEO of commercial entity could direct to build new structure, matching changed environment. And in commercial, very popular form centralized, with powerful responsible CEO, who could after built new structure, fire members of old (this is just impossible in near all OSS projects, as they usually have distributed ownership).
Few words about daughters OSS entities of large commercial. Their difference, while they also like to play Democracy games, but all money still at hands of father entity, and these are extremely powerful levers.
When for some reason, daughter OSS entity become uncontrolled, or just father entity decided, that it will be cheaper to create new daughter entity than to reform old, they just create new daughter entity and make it structure as need.
This is really easy for them, because for commercial entities, just normal to have processes division (department), which just constantly modify internal regulations of entity, to match current CEO view. So as I hear, in modern entities, typical to rebuild structure every 1.5-2 years.
And yes, sure, will be transition from current state to a new one. And who knows, this could be like Y2K.