Even the basic front page of youtube was of immediate and obvious value to a creator, and would increase disproportionately in value the more people were on YouTube. The same goes for Amazon, and the same goes for Facebook.
All the LLM providers are - extremely useful - tools. Currently I can only see the 'non-monopoly' proportional improvement when their userbase grows from 100 to 1000.
But I might be wrong, and I wouldn't be surprised if in hindsight it will be obvious what the real disproportionate advantages there were to be found.