That would work as a text book example with NO defenders, however if even 1 gv made it out this example goes out the window.
To be honest with you, the term taking a "undefended base" is a poor excuse of someone not willing to defend it. Why is that?
Will you die, probably. Could you turn it around and save it, probably.
If there isn't anyone to defend the base, is it the takers fault? No.
Sometimes all it takes is people willing to defend, but we all know what that sacrifice means = dying for it. Some people don't want to defend because it will lower their precious score. Some do defend, and are successful at it. Others don't and end up here on the whining boards.
I could take VB's and ports all night with 3 guys, with Im sure an 80% success rate. I did point out that if 5 guys join a mission you hit a VB or port, this gives you two extra guys with bombs just in case. The point is you don't need 20+ people to do it.
Dadsgun you can honestly say you would have fun being one of two of three guys trying to defend all night against a group of 20+ hitting base after base? where if the "horde" split apart a bit and challenged themselves by working a couple bases at the same time due to having 20+ people wouldn't be more fun for everyone?
Hey Fugitive do you really think I care if Rooks or Knit's have FUN................LMAO!
.........It's all about the BISH having FUN! 
PS- ^^^^^^TOTALLY AGREE WITH YA ON THAT ONE STEVE^^^^^^^^^!
I suppose your the A hole that after a fun night of drinking LETS his buddy drive himself home.... ya your a real fun guy

Lets say for one second I agree with your premise...that missions are bad for the game...and the people who spend their time organizing them are bad people (selfish/clueless/proud) <-- your words
Then why would the solution possibly be expected to arise from THEM changing their behaviors??? Shouldn't the solution be that AWESOME people like you organize other AWESOME people and oppose them??? Oh wait...you and other lone wolve fiter types don't possess the charisma, leadership ability or understand human psyche enough to do it....or you just don't REALLY care enough to inconvenience yourself to spend the time...
OR....MAYBE YOU DON'T GET IT???
maybe there is fun in accomplishing an objective successfully???
Tell you what...you pick your 5 squaddies and try to take a port that I and 2 other squaddies defend against...let me know when you wish this to occur...this port in question did not have a gv spawn so hope you got a good goon pilot 
Man up!!! Can't wait to hear from you...if you don't contact me I'll expect you to stop the ridiculous postings that demonstrate a COMPLETE and UTTER lack of understanding of the game...
I never said that !!! Missions are the bread and butter of squad operations !!! The point of having a squad is flying together and accomplishing a goal...capture bases, stop attacks, even win the war, can we agree with that?
The "horde missions" is whats bad. Honestly how many BOPs would it take to capture a port? Certainly not 20+ ! If you need that many, you should spend more time in the TA than the mains. There is nothing wrong with missions !!! How many times do I have to say that !! 10 guys in a mission can take a small field, you add 4 more to "make sure", the other 5+ hit the nearest VB that spawns to the small fields you are hitting.
Now we have two fights going, even if you only have a few defenders for each they feel they have a chance to defend. Maybe they do and blunt your attack, you regroup, reassess and reattack. Wheres the fun in the first 10 guys into a base flatten everything and the other ten just circle for landing

Challenge yourself, challenge your squad. ANYBODY with 20 newbis can take a base, only a skilled group could do it like I'm proposing.... are you and your buds up for the challenge, or can you only steamroll with 3 to 1 numbers?