Biontech pioneered the mRNA technique and they were sponsored by German taxpayers; and Pfizer was promised by Operation Warpspeed that US taxpayers would purchase 100 million doses of any potential working vaccine before it was even developed, that must have felt motivating. There was no vaccines developed entirely through private funding even though the profits were entirely privatized, ie Moderna received about a billion in development aid and AstraZeneca somehow managed to pocket research out of Oxford University.