When I first started lowland walking, as opposed to hill walking, many of the footpaths were hard to find, badly signed, or blocked by growing crops. This has improved enormously over the past twenty or thirty years, and most farmers accept that walkers have rights of way, and make the paths clear to help us keep to them. It is not always easy, even now. Apart from the occasional bull in a field - legally with a herd of cows, apart from certain breeds, which make many of us apprehensive, some farmers fail to make the rights of way clear. Most of them do, and I have no objection to seeing the words "Private. No public access" - this often helps to clarify the route. And believe me most of us don't enjoy getting lost and wandering through farmland randomly seeking a way through!
Of course we as walkers have to play our part, and make sure that we close gates - sometimes with two catches if that is how we find them. We were caught out by this recently when the first walker didn't communicate with the last one through.
Fortunately the farmer concerned was happy to point this out to us, and tell us why. The cows rub against them and sometimes this opens gates with only one fastening. He also wondered what we'd learned today, and why anyone would want to go walking through his fields at all. But all this was done in a friendly and reasonable manner - on both sides.
We had a different experience some months ago, when we couldn't find a path, although it was marked on the OS map, and wandered into the farmyard to ask. The farmer told us we had no right to be there, and refused point blank to help us find the path. I contacted the local authority to check whether there was a right of way. When we returned from the opposite direction a few months later, all was clear and easy to follow.
Maybe this man had the attitude I've seen expressed on occasions - that public footpaths are an outdated survival from the times when agricultural workers had to walk to work and use the quickest route. Nowadays there is no need for them and they simply provide access for criminals and ne'er-do-wells.
A completely different problem is the way that footpaths are now frequently chopped into pieces by the modern equivalent of fast flowing rivers - major roads. Some lucky places have a tunnel or a footbridge which doesn't add too much time to the walk. it can be both annoying and unpleasant to have to take a half-mile diversion alongside a noisy road. In other places there is no alternative but to wait patiently for a break in the traffic - that's fine if you are just a small group of adults, but I wouldn't like to do it with a large group, and certainly not with children.
A side-effect of this is that certain routes are very rarely used, and stiles can be neglected, broken or overgrown - all of this is an extra disincentive to walking there. We are constantly encouraged to be more active, and walking should be a simple way to achieve this. It shouldn't be an extreme sport of jungle-hacking, awkward stile climbing and traffic dodging.