I'm not sure ops time is even the one to worry about. Most things I've learned I've learned the hard way. So a server going berserk isn't fun, but it's not like I just wasted either time or money on it. I learned something. I better understand my execution environment.
Downtime, on the other hand, is just lost revenue opportunity.
I certainly do, and I can tell you the amount of time I've spent managing servers over the past year has cost us less than running our entire production stack on Heroku would have done. So has the odd bit of downtime we've encountered because I've not got the same level of experience as Heroku's ops team.
Downtime, on the other hand, is just lost revenue opportunity.