I think the challenge with 10 IoT LTSC isn't going to be the OS itself, but the software running on it. Lots of software uses chromium embedded, and in the case of win7 the day that extended support (+3 years) ended CEF also dropped support and required features only found on more recent windows releases, then as other software updated their CEF dependency they also dropped win7 support. It might not be a major thing, but there is a slow erosion that goes beyond whether the OS gets patches. If nothing else, if it's a machine that uses software that goes online it's a notice that you should investigate moving to something else eventually.