Because you’re a woman, and he’s a man.
And also because your way won’t necessarily work long-term
for him, because… (get this!)…
he is not you! 
(I know, I married my opposite, too.)
Seriously, though, men and women generally see “help” in entirely different ways. Your way would probably be quite helpful to another woman (especially one with a similar personality). But probably not so much to your husband. In fact, it may be very harmful to his self-confidence if you were to tell him how he could do his job “better.” It’s a “respect” thing.
For now, I’d ignore his comments about possibly getting fired. He’s probably just feeling a little insecure and you’re likely taking it more seriously than he meant it. I know it’s scary when his income is your family’s main support. But, hey, if he does get fired, it’s not the end of the world. There are other jobs out there just as good, and if he found this job, he can find another one, right? Still, maybe you would feel better about your financial security if you two had some “emergency” savings built up? (To that end, I like Dave Ramsey’s FPU, but there are other financial programs out there just as good, too.)
Despite your feelings, ISTM
his job is really not the issue; it’s the
time you want, so focus on that. And then have faith and let him figure out how to make it work. Let him know that you want to spend more time with him or that you’d like him to be home at a certain time–
not that you think he’s working too much or too inefficiently. Changing how he handles his job is
your idea of how to get what you want, but it’s not the ONLY solution nor necessarily the best solution. Besides, even if he made the changes you suggest, it will not necessarily work for him for any length of time, and then you will be right back where you started!
I know it’s hard and it goes against our feminine instincts to nurture and to help by constantly looking for “better” ways to do things–or to do it ourselves. Sometimes I have to remind myself: “Didn’t I once have faith that my husband could manage his time, do his job, support his family,
and be a good husband and father? Didn’t he live and work on his own before I came along to tell him how? So now I need to bite my tongue and let him do it,
because I know he can. He’s done it before!”
I need to keep my own insecurities in check–they are feelings, not facts. And I have my own responsibilities to worry about, too. I’m not going to sugar-coat it: It’s REALLY HARD sometimes! But it works. Maybe it would work for you, too.
Have you ever read the story
When Queens Ride By? I highly recommend it. If you don’t want to download the .pdf file, I think there are other copies available online if you do a search.
And, of course, I’ll say a prayer for you and your husband to find a “win-win” solution!