Intense? Actually... yes, they sure can be! It's not uncommon to see players put amazing amounts of effort into them to the point where a break afterwards is a good idea.
The time periods between 'serious' campaigns are more a result of mixing a set of factors into putting a campaign up:
-amount of time to design them, which is considerable.
-amount of time needed while the campaign is running to keep it running.
-out of the playerbase, there are really only a few experienced admins who have the time and know how needed to successfully get a campaign up and running. Honestly I feel it's been difficult for these few to shoulder that workload time and time again (something only they could really comment on) irregardless of motivation to do so.
I think Bonk wrote somewhere that the Forge was his effort to always have an OP campaign running. As LordKrueg mentioned it doesn't have a lot of rules normally used for balancing purposes that apply to it, so it's sometimes considered less than serious. Beats me.. I know I've had some white knuckled moments on the Forge the little time I've been able to get to play and some good times that were just like the 'old days' years back when I was really first starting to get into SFC... so I'm happy with it.
Oh yeah, just because your post count is low doesn't mean squat, you're absolutely entitled to a say here and your opinions as much as the next pilot
Don't hold back feeling otherwise.