Why is that a problem. Would you like to grind for exploring, bounty hunting, etc. as long as for trading to be able to be on top of the profession?
you're absolutely right! every body who doesn't trade should be PERFECTLY happy getting to that mid tier ship and never being able to afford anything bigger or prettyer.. there's NO reason they should expect to have any logical progression in the game. that sort of thing is only for you traders and everybody else should be happy with what they have.
BTW, the goal of the game is not (necessarily) having the biggest ship or the most money in the bank.
If you choose it as your personal goal and then choose the most ineffective way to achieve it, then it's up to you.
It's different when it's a game, this isn't real life. This is being marketed as a space combat game and people are willing to "grind" the combat part because it's fun. Noone's saying make every eagle kill a 1mil bounty people are saying they need options for their career to progress so they feel like they're progressing.
E

has never been a "space combat game". Combat was always one of the options to spend time in it, but you could avoid it almost all together and be perfectly happy.
Sticking with the skyrim analogy you're pretty much saying people should stick with flames and not try any of the other spells because you don't need them. If this is the case in elite why do they even have huge hardpoints and guns on the big ships if combat players aren't going to use them? If it's only the traders getting the "bigger houses" then remove all hardpoints from the big ships and only add bigger shields and counter measures as that's all the trading careers require.
If you don't need the other spells in your career path, then it's fine. If you want to have all the expensive stuff, you have to do something in return, rather than just expect the game to provide you with enough money while doing everything else.
On my T7, you won't find any weapons mounted on the hardpoints. Personally, I haven't seen the advantage of big ships in combat (yet?). I can win almost all fights in my Cobra, and an Anaconda or Python would have huge repair costs if something goes wrong.