When I see them near roads etc they seem to be less timid but when I've seen them in natural locations they have scared much more easily.
I wonder how long it takes for them to become desensitised (if that's what's occuring) & the implications this has on their future survival
I'm sure they used to be more timid for me as well. I suspect part of it is that I've got to reacting more sensitively as I see more of them. They can still startle and curl up in a ball if you make a noise or a sudden move, but if you don't they may go around you but don't tend to stop what they're doing to pay attention to you. And even if you do accidentally startle them I find they emerge from the ball if you stay quiet long enough (generally no need to move further away). After all, they are reasonably well protected...
I saw one the other day when out mountain biking. It darted across the trail ahead of me so quickly, I had not the time to react (sonic the echidna ?). It must have been sitting beside the trail and been rather startled by a noisy bike.
I had never seen an echidna in the wild before, although I doubt I really 'saw' it. I seem to not have the same luck that you have in finding them, but perhaps it is just because I don't look hard enough (they do blend in a fair bit I would imagine)
I suggest not looking for them but listening for them (hiking alone probably helps me). Sometimes I've seen them first, particularly in open, grassy areas, but mostly heard them first then seen them. Because that's another part of them not really caring - they don't seem to try and stay quiet at all, because they're just intent on their ant-hunting mission.
For comparison, the one in Healesville (well, Yarra Ranges near Healesville) was a trail down from Mt St Leonard through a relatively open grassy area on either side. I saw a wallaby a long way out, and despite approaching as quietly as I could it wouldn't let me within 25 metres of it. When two minutes later I heard something in the grass to my left I was pretty sure it
wasn't another wallaby, and was probably an echidna. Which it turned out to be.
Just around Melbourne I've heard (and seen) them in at least the Dandenong Ranges, Cardinia Reservoir Park, Lysterfield Lake Park, Sugarloaf Reservoir Park, Yarra Ranges, Phillip Island. So they're certainly about.