I think this reasoning (that is, doubting PoW value like that) is wrong. The problem of "conventional banking" is not in said overhead.
It's wrong to compare an average bank electricity consumption, plus it's workers salary with Bitcoin/PoW alts consumption.
Bitcoin doesn't eliminate banks. Banks are the ultimate liquidity providers to enable capitalism. FRB evolved because the demand for money exceeded the supply of gold. Should Bitcoin become the dominant currency of the world, banks would need to apply FRB to it as well to help control the price or risk massive waves of bankruptcy in a deflationary event. The alternative is banks won't touch bitcoin. Without demand for bitcoin investment capital, it will likely always remain niche.
Fractional reserve banking is setting the rules for economy and politics that benefit bankers, and damages everyone in the course of that.
Fiat money exist as debt, so whoever has better "credit rating" can go deeper into debt and benefit from inflation, or from devaluation of his currency towards the reserve currency, currently USD.
So called credit rating is under gross manipulation by powerful interests. This leads to the clusterfucks like in 2008.
While true, there is nothing special about PoW in this regard. Any decentralized currency combats these problems.
"policies that result in savers earning returns below the rate of inflation" in order to allow banks to "provide cheap loans to companies and governments, reducing the burden of repayments"
This siphons money from workers who hold deposits or bonds (e.g. indirectly in pension funds) to the shareholders, who are already rich.
Historical savings interest beats inflation. It is only in the last decade or two that basic savings interest has not kept up with or exceeded inflation. The stock market will generally always meet or beat inflation as long as an economy grows as it is automatically indexed to inflation by the investment of inflated currency thereof. The "theft" via inflation is highly dramatized. It is government spending (and other interference) that causes a misallocation of resources, not inflation. In the case of the 2008 crisis, it started as pressure from the US government to the banks to issue more mortgages to less qualified people, distorting the checks and balances of the system.
Whereas PoW baskets can be woven by anyone with free time and necessary skills.
You mean anyone with custom, production monopoly-prone specialized hardware.