I think this might become more common over time.
Up to this point, a lot of the news company's online presence was probably pretty cut and dry. Some of my local news stations have terrible websites that take forever to load, yet those websites were probably cutting edge at some point. One of them has a layout that hasn't changed in at least 10 years.
If their IT department hasn't expanded their skills beyond making and maintaining those original websites, I could totally see a long delay happening before/if they join the fediverse.