Not true. There is (or at least until now, has never been) a reason for video or 3D professionals in the "Arts" to use anything but GTX cards. 3D CAD and AI professionals on the other hand will profit from the Quadro cards. The main difference between Quadro and GTX were amount of memory, clock speed, longevity and drivers. GTX are faster clocked but relatively less reliable. GTX are game optimized, Quadro drivers are CAD optimized (extremely so) GTX are much cheaper, but may have a shorter lifetime (but who runs a render farm on 10 year old cards...) GTX offer very fast single precision calculations, Quadro single and double. Almost all 3D rendering is done single precision.

It's a spectrum. Not every professional wants and/or can afford the top end cards. Many professionals (i.e. those who make money doing a thing) have been using high-end gaming cards for work pretty much since they existed. There's also the long-running debate as to the actual value of the 'pro' line of video cards for non-mission critical purposes (enough of one that nVidia in their license prohibited the use of gaming cards in servers with the odd exception of crypto mining)