I get that you want us to fight, but...a huge part of the problem is just... how do we actually DO it? what am I supposed to actually do?
I tried trading in some biowaste and I got a glorious ~2 merits per ton(as my Power's focus activity!). That's about 8000 merits per hour of undermining, in a perfectly efficient cutter. Of course I can add a few holoscreen hacks here and there, but that rapidly loses you local rep which makes that approach self-defeating, AND the range on recon limpets is short enough you can't even hack AND dock to trade at the same time! Plus, you end up burning hundreds of millions on donation missions just to keep your rep up, and you have to sacrifice a lot of cargo space to carry the limpets and controllers, too.
Meanwhile LYR is pulling 144,000 merits per hour rare goods trading. The math just doesn't math there. There's a really good reason why sniping has been the main way systems have been lost thus far. In practice, you could TRIPLE undermining and it STILL wouldn't come CLOSE to the effect it would need in most cases. Stuff like Piracy and Smuggling too, which really should ostensibly be prime ways to attack each other, are completely ignored. Shouldn't Delaine, the Pirate King, be making a lot of his merits, you know, PIRATING?
The problem you're really running into here has nothing to do with the balance of reinforcement vs undermining and everything to do with the fact you're basically making combat the only way to undermine - and combat, even in power conflict zones, is a pretty awful way of earning merits, for a LOT of reasons.
For one, power ships are heavily engineered, so even with a fully engineered ship of your own you're going to be spending a lot of time getting kills. To efficiently get merits that way you kinda need multiple players engaged, so the only way is to get a full wing in one system at the same time! But that means swapping ships and moving around which takes a lot of time, time which COULD be spent solo fortifying or acquiring, activities which work just as well solo, and with all players playing at their convenient times and time zones!
This is compounded by the fact you've also senselessly prohibited multicrew players from getting any merits, stopping up the easiest way to get extra firepower and merit earning. It could be an amazing mechanic to have four players in one ship all earning merits, but that, like smuggling and piracy, is completely off the table right now.
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If you really want to make undermining more popular, just make it easier to actually DO.
- Add Smuggling and Piracy as dedicated activities.
- Allow multicrewmates to get merits as long as they shoot something(fly a fighter/run a turret/etc)
- Boost the range on recon limpet controllers to allow simultaneous hauling and hacking(and fix the limpets getting lost, too, while you're at it)
- Buff the inferior merit-acquisition methods, too. Many of the methods of undermining are completely underwhelming.
Power Malware: Uploading Power Malware, for example, takes a prolonged period of time and caps out at something like 24,000 merits per hour WHILE DOING IT (IE, downloading / uploading). For comparison, downloading Power Industrial Data offers ~96000 merits per hour while doing it. A good way of doing this would be a large merit chunk given if you upload malware in all dataports AND a big bonus if you upload malware without being caught. Right now, stealth is completely disincentivized compared to just killing everyone there. If you could get scaling bonuses for not setting off any alarms, not alerting any guards, and maybe even for going completely undetected, that could really encourage people to get out and be sneaky.
Hacking holoscreens is spammy and almost irrelevant too. What if hacking a holoscreen LASTED, and gave a constant trickle of system points for a few days or until it's unhacked? The player would get a big chunk right at the start, instead.
Scanning megaships is a nice bonus but not nice enough to actually be worth doing.
Spamming low-value goods is a fundamentally problematic approach too. It doesn't make any SENSE, for one. Why should dumping cheap goods hurt another power? Why can't the station just refuse to accept them? If they cause them problems, why can't they just destroy them? And what do they expect the defending Power to actually DO about it? What if instead you changed it to 'eject goods near stations'? That way the debris clogs up the space lanes, which at least feels somewhat justified as an attack. And you could synergize that with other bonuses like committing crimes, if you wanted to do so inside the no fire zone. You could even make DESTROYING debris a merit-gaining activity, and spawn occasional trash about 10-20km out from stations, giving players something to do on the way out from a station.