The loss of color is concerning, but something I find interesting is the image the author chooses to illustrate Loos' quote, "We have achieved plain, undecorated simplicity." I would argue the building pictured falls short of this goal in important ways. A lot of contemporary architecture lacks the modernist commitment to flat planes, pure volumes, etc. and adds lazy and useless decorative/textural elements. The building pictured would look better if it was less adorned! (But even better with some color)
The ugliness of the contemporary world isn't a result of modernism, but rather neoliberal indifference to beauty.