You cant just "fund a startup trying to make ram". Chip fabrication is probably the most difficult and capital intensive production process there is. What manufacturing more ram looks like is investing tens of billions of real money (not the you give us stock we let you use our GPU deals the AI companies have been doing) and then waiting 5-10 years before the fab you funded starts to make chips, and hope prices are still high by then.

That's why the existing manufactures are slow to scale up, they arent sure that the current spike in demand will still be there by the time their scaling up increases production.