The work is never done right. You talk about engineers and programmers right? Well they should know that their work never ends; there's always the need to continually improve the product so that you don't "fall behind", fix the rampant bugs that occur when you add in new features, fix the bugs that were caused by you fixing the previous bugs, realize that the customers actually wanted something different, need to refactor the code properly to match the latest design fad, have to rewrite the program in a brand new language...
And all this work has to be done. Because if you don't continually upgrade your product, then your product will quickly become old-fashioned and obsolete.
So, when we say "there's no work to be done", it's a blatant lie. Either it is an excuse we make up so that we can leave something that we obviously hate doing, or it's because our employers are unwilling or unable to pay for it to be done. Lying may make you happy, but it makes me less happy. I prefer misanthropy over delusion.