A lot of it is also the fit (between the cock and the woman) and how the guy fucks her. Not every girl who CAN cum from intercourse will cum with every guy.
A big cock with good stamina helps, but isn't the instant cure. My best friend is a lot smaller than me but he has made two of my previous gfs have multiple orgasms from intercourse and I never was able to, but then again I had sex with one of his gfs (we've shared since we were 16 haha) and made her cum by going deep against her cervix and grinding my pelvic bone on her clit (as described above) and gave her an orgasm he never had.
We all fit differently.