Where is the adventure? It is wherever you left it.
Blaming National and it's rules and it's attempts to keep the organization alive by adapting to the times and to the attitudes of todays youth and parents is easy and we seem to do it all the time. I'm going to be bold here and say none of it is National's fault. None of it. Let me repeat that - None of it.
National, Region, Council, District - they aren't leading the boys. Volunteers in Troops, Packs, Crews are. Is your unit providing adventure? If not, why not? Because National has all these rules? Let me be blunt - National does not have these rules to protect you, the chartered organization or for that matter the boys. It may appear that way but the reality is National has all these rules to protect the corporation and it's sub-corporations (Council). They help to provide a layer of protection against lawsuits and insurance claims - and that's it. If you're on an outing and you failed to follow the Safe Swim Defense rules and a Scout dies - National can point to their rules and show that people in the Unit were trained (why do you think they're doing online training on these things, and requiring all chartered volunteers to complete it if not to be able to pull up those records as evidence that the Unit Leaders were aware of these rules) and say that National/Council is not at fault and that the fault lies with the unit and the volunteers (and to the Chartered Organization who chose and approved of the leaders). These rules aren't created out of a vacuum - they come from something - and that's often going to be some lawsuit or insurance claim that landed in National's lap. National didn't just decide one day that 13 year old boys couldn't use a power drill - someone, somewhere down the line was using a power drill, got hurt and the parents sued.
No one is being 100% compliant with the rules - most likely not purposefully, but we all know units that will ignore a rule they don't like and do a work-around to do an activity that is banned - calling a Troop just a bunch of friends getting together on their own to play laser tag with the Scoutmaster and ASM's is one of those things. We probably all know a unit that doesn't even bother with a work-around and will just blatantly ignore rules they disagree with.
The thing is, even diligently following the rules, there is still plenty of adventure out there, but that's for the units to provide. National and Council provide some of the tools, but they aren't going to handhold you through everything.
If there isn't adventure in your unit then you need to look at your unit. Yes, a Troop should be boy-led but we as adults in the unit have to start being a better resource. Telling the PLC to go research and come up with the program themselves isn't the best way to ensure that adventure abounds in the unit - but having the adults plan it all isn't the best way either. The best way is for the Scouts and the Adult Leaders to work together to create that program - the Boys decide but you get to advise and in some cases consent (it doesn't do the Boys any good to plan a weekend camping trip to a cave 150 miles from home if there aren't enough adults around willing to provide the transportation and help with the logistics). Don't just let the Scouts loose on the internet to research camps and campsites - I know folks like to claim that their 13 year olds are better at technology that they are but the fact is, that 13 year old still is learning about things like researching and critical thinking. Anyone can type in "campgrounds near your town" in a search engine but sorting through the information takes some skill, which comes with experience. Anyone who has ever done a research paper in high school then does a couple of research papers in college will tell you how little they actually learned in high school on how to research - and any one that has a Master's will tell you they didn't really know anything about researching until then - and we expect our 13 year old boys to be good at it? This is where we as adults come in to play - we help them research (not by doing it for them but by guiding them through the process - and I'll bet that is most of the successful boy-led units out there, some adult had already done a lot of research into camps, etc. - not to hand it to the boys but to know what the Scouts could expect to see) and we help them think outside the box - we guide them through the brainstorming process - sure, the SPL may be at the front of the room leading the session, but an occasional nudge from the SM or ASM in the meeting can go far. An out of the blue "do you think anyone might be interested in a weekend canoe trip?" can help get those creative juices flowing.
If your unit is truly adventurous, then it should be really easy to recruit - if your Scouts aren't successfully recruiting, maybe its time to look at the program your offering.
Summing up - Stop blaming National for the shortcomings in your programming. Instead of looking at these rules as things you can't do - try to see the things you can do - and there are an awful lot.
Oh - and Summit and Seabase isn't High Adventure? Check your adult bias - to a 14 year old boy from Iowa, a week at Seabase will be a high adventure. To a 15 year old boy from Kansas, a week at Summit learning whitewater kayaking will be a high adventure.