It is simple risk and reward that keeps people off Beta.  It is not worth it most of the time to put your mining bot at risk for slightly faster mining.   Heck most of the time when you mine it is afk watching something else.  Mining on Beta is Risky because it is so hard to disappear and once you get spotted you are done and it does not matter if you are in a guild or alliance on that beta island or an independent you are done because until the threat goes away the minor bot is put away.   So when it takes hours to mine up mats for something it is not worth the risk. Other than for guild ops relating to the Epitron only available on beta mining not worth the risk!

I suggest:
Shrink the influence ring of the guilds on the island to closer to their station buy proving excellent benefits close to base.  Say great mining and combat bonuses next to the base and make it much easier (many more port in and spots) for people to get on and off the Beta island.  This would make it harder for guilds to control access to the beta island and at the same time give guilds the ability to protect guild mates without controlling the entire island.   But you also need change to the gates.
Most of the time when you drop onto beta you are either looking for trouble or not wanting to find trouble (mining/farming).  Either way you do not want to be jumped right as you drop in. So how to stop M2S from having a person sit in an Ark all day long on one of the only 3 port in spots for 8 to protect everyone on the island?  This only takes 3 people to sentry the entire island. You can
1)     Change the warp in point immunity and make it timed. This would make it much more difficult on the Ark sitting there announcing everyone who comes through in alliance or guild chat. 
2)    Put in more gates but make them one way.  This way once you are in then you are committed but there are many more ways off the island.  I would suggest 12 more gates 6 in and 6 out for each island.  This would make it much more difficult to deny access to an island.  Rewards are great but you have to believe you have a good change to escape with your loot.
3)    Either make the islands bigger or shrink the radar.

What all this does is: Makes it much much harder for a guild to control access to an entire island and at the same time provides different bonuses and protection to guild mates mining farming close to base.  This should open up the island to more people.   More people on the island translates to more PvP.  People want to be able to dash in pick a fight/mine/farm and get away. When all 3 ways on and off the island are guarded that is extremely hard to do.

Laf