The Portugal experience sounds fantastic, but what, over a decade ago or so we in the UK had CYB pioneering and all the Welsh trail centres and uplifts followed, FOD, Cannock etc, 7 Staines and other Scottish places all funded through various means and plenty of active volunteer groups. Much of that has literally rotted away but go to some places and they are more popular than ever, some almost deserted, funding for maintenance/ rebuilds very limited and a shit ton of red tape which pretty much prevents volunteers doing anything worthwhile.
Locally we recently had massive funding for the commonwealth games, some of which provided a new family trail which is very popular, there is a dedicated DH area run and maintained by a few dedicated people, a couple of still very popular but getting a bit run down/ dumbed down XC trails, used to be some very well attended XC dig days but thats finished ( red tape) but lots of off piste to ride for the Youtube gopro vloggers.