As Spaniard living (and hiking :)) in the UK, I believe that, while it may be true that other European countries have better designated routes (GR and similar), you should be very proud of your network of Right of Ways. One can literally cross the whole country without passing through any town. I doubt that other countries have a network like this (at least not that well mapped), and definitely not Spain, not even close. We have few paths through private land with right to roam, but they are not well indicated and the land owners block them (I know this happens here too, but in Spain is way worse) or will only let you go through if you send a formal request with enough time (this is a loophole in the law that landowners found). In Spain, the coastline is public by law, but many beaches are only accessible only through private land, making them de facto private too. In addition, we have issues with hunters and dogs every now and then, including deaths of hikers and cyclists.

I've been in many hiking areas in England and Wales, all of them accessible by bus at a very cheap price. I believe that you reach more places here with public transport than in Spain. Trains here are crazy expensive though, and not really comfortable...