100% disagree with OP. This entire thread is based on the false premise that making profit is the only way to "progress"
If you're good enough, you can become Elite in a sidey.
I think the OP is addressing the scaling of different professions, rather than whether it's possible to reach Elite or not in the default ship. Say you want to go to Tokyo, you'd probably want to walk to the bus terminal/underground, then take the train, then take the bullet train/airplane, rather than taking a month to walk hundreds (or thousands) of miles. You could walk/swim all the way, but it's a stupid thing to do.
Multipliers should be introduced for bounties so it encourages teamwork to take down contract targets rather than jockeying for last-hit like MOBAs, which should present significantly more challenge than what they are now. Wings would let any ship become a viable target for pirates - right now, why would you attack an Anaconda when you could only scoop ~20 cargo? With wings, you could attack one and 4 of you could each scoop 20.
IMO trading should always be the highest earner, by a significant margin - how else are traders going to afford escorts, if and when Wings becomes reality and pirate attacks become coordinated? In the current situation, trading income
cannot let even the most high-earning trader pay even just one player as much as he could earn from simply bounty hunting without eating say, 25% of profits - there is no incentive to fly escort duty. For the average trader, that's probably 50% of profits - no sane trader would sacrifice that much.
Escort duty is space trucking without hauling goods, unless you're flying a high-risk route. How many players would want to do that? Also, hiring for escort duty means exposing your trade route - what's stopping the escort from selling route data for say, 10 million credits? I'd buy a 3kCr/t route for that in a heartbeat. What's stopping him from backstabbing you by telling pirates that you're hauling some high-value goods in some freighter?
I'll be brutally honest - unless you are looking for player interaction, there is zero incentive for a trader to be playing in open. Not may people are willing to lose hours (and I do mean hours) of work for more 'fun and excitement', but pirates need traders and bounty hunters need pirates. Once all this multiplayer stuff gets introduced, unless some mechanism is in place for traders to defend themselves effectively, you'll see more and more of us joining PvE groups or solo mode, because even armed freighters stand a ghost of a chance against more than one attacker at a time in the current meta. There needs to be some sort of mechanism to defend against wolf-pack tactics and dumbfire spam (think flak cannons).
So, as it stands, trading income is fine and other sources need to scale more. But hopefully the changes to come would make every role more interesting to play.