I think Switch will become the biggest system of all time, selling more than PS2. At the very worst will sell 150 million.
PS5 will sell good but less than PS4, i expect something between 100-120 million.
2020 predictions: NSW 25m, PS5 6m, XSX 4.5m, PS4 9m, XB1 3m
In December 2019 i predicted 21m Switch, but that was before COVID, obvius increased my predictions.