The largest "monitor" I can see on Newegg right now is 48" diagonal:
https://www.newegg.ca/lg-48gq900-b-48-uhd-120-hz-refresh-rat...
And that's an outlier— most are 27-36", with 32" being the overwhelming sweet spot.
In contrast, my TV is 77" diagonal, and most people would consider 55" to be about the minimum size for a new TV at this point, outside of special applications such as the bedroom/kitchen/etc. I don't know where I'd begin to go about purchasing a 77" 4K display from a digital signage vendor.