1. Donationware - Let's be real, tokens are expensive and if they ask for everyone to chip in voluntarily people wouldn't do that and Ollama would go bust quickly.
2. Subscriptions (bootstrapped and no VCs) again like 1. people would have to pay for the cloud service as a subscription to be sustainable (would you?) or go bust.
3. Ads - Ollama could put ads in the free version but to remove them the users can pay for a higher tier, a somewhat good compromise, except developers don't like ads and don't like pay for their tools unless their company does it for them. No users = Ollama goes bust.
4. VCs - This is the current model which is why they have a cloud product and it keeps the main product free (for now). Again, if they cannot make money or sell to another company Ollama goes bust.
5. Fully Open Source (and 100% free) with Linux Foundation funding - Ollama could also go this route, but this means they wouldn't be a business anymore for investors and rely on the Linux Foundation's sponsors (Google, IBM, etc) for funding the LF to stay sustainable. The cloud product may stay for enterprises.
Ollama has already taken money from investors so they need to produce a return for them so 5. isn't an option in the long term.
6. Acquisition by another company - Ollama could get acquired and the product wouldn't change* (until the acquirer jacks up prices or messes with the product) which ultimately kills it anyway as the community moves on.
I don't see any other way that Ollama can not be enshittified without making a quick buck.
You just need to avoid VC backed tools and pay for bootstrapped ones without any ties to investors.