HO- vs CH3O- ?
first thing it is because of experiment.+ H[+]+ H[+] . Conjugate acids are CH3OH and H2O. Pka values for CH3OH and H2O are 15.5 and 15.7. So CH3OH is strong acid than H2O. Conjugate base CH3O- is less basic. So OH- is stronger nucleophile than CH3O-"
but normally RO- is more than OH-