I'm sorry you feel guilty SmileysPeople. At least you made some effort with your MIL. If she had really been such a wonderful person as all her friends are making out, wouldn't she have welcomed you more?
My MIL will probably die soon (though I've been saying that to myself for 10yrs...). I can't imagine anyone describing her as a wonderful person, but I dare say people will find it easier to be hypocritical than to tell the truth.
When old people are not close to their families people usually blame the families and assume they're selfish. (I used to do this too). It's hard for them to see the wicked and noxious bitch inside the white-haired old lady with the rather vacant smile. And I'm pretty sure MIL's never been as evil to anyone else as to me, because no-one else has threatened her illusion that she's the sole centre of her son's world.
Some guilt on our part will be unavoidable when MIL dies, as we've had hardly anything to do with her for years. But she spurned all our efforts to build bridges with her.
She lives five hours away and has been in hospital for the last two weeks. Dh has still not managed to speak to the consultant to find out what's wrong with her, which seems neglectful even to me. He keeps telling me he's forgotten to ring when I ask. But under this 'forgetfulness' I suspect there's still huge anger and resentment at the way she's treated us.
There's no point in our case regretting the loss of a loving granny to dd. She wasn't loving - she didn't hesitate to use dd as a pretext for trying to pick a fight with us. She resented dd for taking dh's attention away from her. There are plenty of people in dd's life who really do love her.
Hope you will be able to gain a better perspective once the first wave of reaction has passed