There are a lot of nuances in this issue that don't easily fit in a 350 word article targeted at a general audience. There are a few different issues which are muddled together here, so let's see if we can disentangle them a bit.
On asset allocation, most of the large MySuper funds being discussed are from industry funds. Most of them have a significant allocation to direct infrastructure and property, neither of which have been that well-proxied with passive approaches historically - it is reasonable to ask whether it will continue in the future with more competition for these assets, or whether the lack of liquidity in these assets means we have not been paid a sufficient premium to hold them, but in the one path of history we have experienced it has been a successful strategy.
Then we get into specific asset classes. We should be cautious here too. On the one hand for Australian Shares and Bonds, industry funds have been able to keep costs low and pick good investment management. Based on more recent performance I'd argue it is getting harder to outperform in Australian Shares, but when you can for instance get Australian Super's Australian Share investment option for 0.30% it is unlikely to be a big mistake (but equally I would not expect large outperformance given the size of their Australian Share portfolio, nor would I usually pay much more than that). On Bonds, there is only one widely cited passive benchmark used in Australia (from UBS, plus S&P use their own) so extending maturity and/or credit risks can often be rewarded at some points in time. Broader bond indices (including non-financial corporate bonds) aren't as easily replicated as share indices, and even Vanguard in the US has many of their bond funds as non-index funds (but still focused on keeping costs low, much like the better industry funds).
Other asset classes have a less impressive record which is diluted by using figures for MySuper/balanced funds. In particular, I'm not convinced that Australian superannuation funds have done such a good job at International Shares and passive costs are now around 0.2% p.a. or much less (although no super fund I know of has a non-direct offering less than about 0.3% p.a. including admin costs). To pay more than that I'd want more transparency around what we're targeting (for example, if targeting the Value factor I'd want to know what we're getting that DFA couldn't provide for 0.3-0.4% p.a.). Similarly, I'm unconvinced that Australian superannuation funds have premium access to the best private equity or hedge funds (in infrastructure we seen to have local expertise) and without access to/ability to find the best of these we know the average contribution provided by these funds to a portfolio is unlikely to be a great one.
Also, keep in mind that most for-profit funds still charge more on a like-for-like basis. For example when you compare Australian Super's Balanced fund (around 0.6%p.a. fees) to ANZ's Smart Choice Super (0.5% p.a.) you're ignoring that 20-25% of the Australian Super fund is direct property and infrastructure with whatever costs and benefits that comes with. A fairer comparison would be with Australian Super's Indexed Diversified fund at 0.21% p.a.
So, my TL;DR: There is likely some alpha in Australian Share portfolios held by these funds but I expect that to continue to decline over time. There is more competition for good infrastructure assets now but there is still probably an expertise 'edge' that the industry funds have here, so if you believe access to direct infrastructure and property is valuable then industry funds seem a good place to get that exposure. But I'm unconvinced on assets for which there is much greater global competition (international shares, private equity and hedge funds)