No it doesn't, but if most of the endo is on or around the ovaries fallopian tubes and outside of the uterus then it might help a lot, but with severe endo, it could be and probably is on most of the neighbouring organs by now too.
The bonus of a hysterectomy is that it stops you ovulating and stops the endo from receiving the oestrogen it feeds on, but because you are now without ovaries they put you on HRT which does add back oestrogen.
Don't be too hasty, if you can manage a few more periods till the mirena kicks in, it could save you having a hysterctomy for a few years yet and really help with symptoms.
It worked a treat for me. 16 months without a period (I'm mid 40's) and then last week all change I had a proper period with pains and sickness and I felt and feel like death warmed up again.
I hope it's only a temporary glitch and the mirena gets to work again. If it doesn't then I will have it replaced and try again.
I'm stage 4 endo on everything too. Not had kids though.
I am minus one ovary (don't miss it at all) and it wouldn't bother me to have a hysterectomy either to be honest, other than it is the one place than can hold a mirena, so I'm keeping it in me for as long as I can just so I have a thing to put implants in, such as the mirena and perhaps try out any new ones that come on the market.