The bigger problem for making balance impossible I think is that the different professions have completely different cost-benefit curves.
If exploration pays enough to be worth anything when flying an Anaconda, it'll be ridiculously overpowered when flying a small ship. If balanced to be similar to trade in small ships, it'll be bringing in nothing worth mentioning towards the Anaconda's running costs. Making ship costs closer to linear with respect to their cargo capacities wouldn't really do much to help with that.
I would argue that this is the case already, for exploration and a lot of other activities. It’s the ridiculously high ship and component costs, and balancing rewards to match those costs, that’s made the world of ED so nonsensical these days. It's also closed the door on some old existing gameplay that I enjoyed, and prevents some potential for worldbuilding that would lead to interesting in-game decisions.
Let me give you three examples:
Since I'm eating breakfast....
1) In the world of ED, a family of four can eat "healthy foods," for about 4000 credits at the galactic average. That same family can survive on food capsules for about 1000 credits. Taking a quick look at the commodities board on the station I'm currently docked at, I see that the station is currently
desperate for food, any kind of food
. In the original Alpha, the profits of
food canisters alone would've been considered good, at 550 credits/ton. Natural foods? Animal meat would've been close to the "ideal" profit margin, at 920 credits/ton. Since the introduction of high-margin commodities, even these commodities aren't worth the time to trade, and trading in general isn't worth doing, compared to mission rewards, core mining, and even
combat.
Incidentally, if one uses the "corn price index" as a guide for real-world to credit conversion (on the basis that everyone needs to eat), I usually put the conversion rate at $4 USD/credit. So a minimum wage job in ED would pay about 4000 credits/year.
Dashes across a docking bay completely devoid of any gameplay activity, just to look at the on-foot boards
2) In the world of ED, a commander buy a ton of personal weapons for about 4750 credits. The Pilots' Federation concourse is currently gouging Commanders for
pistols for 50,000 credits, or more than the cost of a Sidewinder. These prices are necessary due to reward inflation.
3) In the world of ED, a simple in-system on-foot courier mission, threat zero, is paying about 75,000 credits. The cost of an in-system Apex taxi, round-trip, costs about 200 credits. This level of reward was deemed necessary by Frontier to compete with ship-based rewards at the time.
If Frontier had fixed ship and module costs during the Alpha, rather than inflating rewards, we wouldn't have such nonsensical prices and rewards these days, and commodity trading would still be considered the baseline activity to balance out other activities with.
As for the "a Sidewinder is as good as an Anaconda for exploration" phenomenon? That's because there's only two ship-based activities to do in ED, combined with one SRV activity. More, and larger sized, exploration modules (with properly scaled rewards) would go a long way towards making larger ships something other than a status symbol for exploration. And to tie it to ship interiors... imagine several of those exploration modules being in-game labs where you take biological (and geological) samples for analysis.