The issue is non-technical people don't understand what those are and care even less what some IT nerd is complaining about. The more intelligent ones with more sociable IT staff might even be brought to agree in principle, but talk about taking the network offline for serious upgrades (and the money to buy equipment/software/extra staff for said upgrades) and the door slams shut.

On a micro-scale, I got my sister (a political science major now working for the UN) an SSD for her aging HD-based MacBook two years ago and offered to install it for her, do a complete system transfer. She was all gung-ho until I said I'd need to take her laptop offline for a few hours to do the transfer. She'd rather deal with firefox taking 30 seconds to load, and waiting minutes to switch tabs, instead of taking a few hours on a weekend for an upgrade. She simply thinks she can't be out of contact with her coworkers for that period of time.

Sadly I think she's more representative of the general population than anyone here is.