Right angle wall plug on power cables

In a recent discussion re. audio power cables I was wondering why we don't see cables with a right angle wall plug?

I am particularly interested to hear from audio engineers or folks with an engineering background, not just opinions (like mine would be) or consumer experience. While opinions and experience are helpful, I'd love to hear from the experts. :-) 

Are there reasons power cables not offered with a right angle wall connection?

BTW, an interesting review of a " 27 Best Audiophile Power Cables", Jay Luong at Audio Bacon
https://audiobacon.net/2019/08/17/27-audiophile-power-cables-reviewed/

Thanks!
Dr Eas