I think the issue with grey is some people went all in, and used the wrong greys, a lot of steel grey, blue grey, dark charcoal grey, which made rooms look cold , instead of the softer warmer greys, and they did everything grey, sofa, lamps, rugs, flooring, walls. One big mass of grey.
Hence it fell out of fashion as it didn’t look good and became the live laugh love of interior decor. Grey done well can look fantastic.
there is a woman on our local selling Facebook trying to sell all her grey furniture, says she’s changing colour scheme. And from what I can see no one is biting.
decorating a house with what you love is key,not what is fashionable, else you will soon enough have issues.