Do you know why Moderna and Pfizer decided to develop vaccine injections instead of nasal sprays?

Apparently there are doubts about the ability of injected vaccines to produce antibodies in the nose and throat. I have no idea when those doubts first surfaced; however, I would think that the great minds behind vaccine development realized the difficulties much, much earlier than the common Joe. Obviously a nasal spray vaccine would not have that problem. Nasal sprays for preventing the flu have been used for many years now – see https://www.cdc.gov/flu/prevent/nasalspray.htm

Also, somewhat belatedly, we are learning about research into nasal spray vaccines for covid. See https://www.webmd.com/vaccines/covid-19-vaccine/news/20210119/nasal-spray-vaccine-for-covid-19-in-early-trials. and
https://consumer.healthday.com/b-1-19-nasal-spray-covid-vaccine-shows-promise-in-animal-trials-2649938724.html

Hence my question.