Yes. I bring everything back to this. I can invest in VAS, an ASX 300 ETF, get 10%+ return at a cost of only 0.14%. Any other idea has to outperform that to make it worthwhile. Now active investing can outperform, particularly if you're good at it. But if it doesn't return 10% ish after fees, then it's second rate.
Inflation is certainly very significant over time, so that's important. However, it is consistent across the board, so I wouldn't factor that in when comparing investment style A to style B. But if you're retired and withdrawing, say, 5% a year, then inflation is highly relevant, because that makes it 7.5% you need to earn just to stay even.
Your statement about 8% super return sounds like about right. A good balanced fund should return 8%+. The fees in super I find horrendous! Around 2%, and inferior returns nearly always to the ASX index, which I can get for 0.14%. Riiiight. The tax advantages are the thing that makes super worth looking at.
The superannuation objectives depend on which investment choice you make, and they're vastly different between different options. For instance, a balanced option will say something like this:
