I agree with you. I'd like to expand soon but until I'm totally satisfied wih my roster, I won't be dong so and I'm not going to expand before I reach them EBBL (or max out my prices, if I fail to promote) because I am going to need to improve my team further whether I promote or not.
Ultimately, the ideal solution is a bit from column A (expansion) accompanied by a bit from column B (increased ticket prices) according to where you are in the league system, what your team is doing now, what your player needs are, how much cash you have, how well you fill your arena...
Admittedly, I wouldn't have expanded as aggressively as you have but then I wouldn't have step-traded either, so really your economy-first approach is a win-win situation for you and will, long-term, provide you with a substantial financial advantage over your opponents. Then again, not everyone can follow your system, so the opportunities are limited, and your opponents
may experience a brief competitive advantage over you (perhaps. If they're good).
For new teams - like the OP - rapidly building up the arena at the expense of obtaining good trainees and good position players is probably not the best move. Or so I contend