True for shared environment but WP does fine even on a low-end vps. 2-3 years ago I helped someone setup wp on a lowend vps server which successfully handled ~5million pageviews under 24 hours, the vps had a measly 1gb memory and the memory usage never went over 700mb. nginx/php-fpm/varnish/apc/w3t done. Took me less than 1 hour to set it up.
I don't understand when people complain about wordpress being bloat but at the same time wants it to solve all kinds of problem right out of the box.