My PIL are pretty good actually (in fact they sometimes stay in a hotel even though there is room for them, as they recognise we all need our space!)
But my mother.. well, she says it is due to health issues but it's not stopped her from driving to Holland (she lives far down in the south west, we're Londonish area) or even holidays abroad. So I am unconvinced.
In ten years she has visited us precisely four times, most times immediately after the birth of a baby so she can hold it for a bit, pretty much.
On the other hand we have dragged all the children on epic 8 hour (if the traffic is good - 15 hours it's been sometimes) car journeys across the country with all the costs and effort involved with that. We pay £1000+ for a week in a cottage in the tourist resort she lives in, as there is no room at hers, and DH has to take time off work, we lose paid for days at DCs' nursery, we can only go in the school holidays so the crowds and prices shoot up. Or she could pay £40 or so for the train, get dropped off at the station her end, get here in five hours without changing trains, we pick her up from the station (so no walking involved at all except from drop off zone to train) and she can stay in our spare room and never leave the house if she wants. But she won't.
I love my mum very much and would love to see her more often but we can't afford to. I wish she would make a little more effort, she knows she doesn't have to do anything when she's here, I just want her company. There's never any problems/fights/anything at all on the rare times she does come - she's very laid back as are we. I think in her case she just likes her creature comforts around her basically. Plus she smokes, we're smoke-free and we ask her to use the private sheltered patio with chairs etc outdoors - maybe she can't face having a smoke without relaxing on her sofa, who knows. I think the health thing is a red herring as really it's far less effort sitting on a train for a few hours with a good book than a trip round the shops which she regularly does.
DC4 is due in March so travelling for us will be even more complex!
So yes, I hear your frustration!!