The advantages of tax-loss harvesting in index replication are becoming more and more clear. The benefits are small but both significant and consistent and would make a fund that has returns larger than standard index funds (which would likely put it in the top 10% of all funds consistently). As shown by the Weathfront 500 technology behind the process is not particularly hard. There is clearly some advantage to being the first mover in this kind of space (see Vanguard). As a kicker people clearly hate taxes with a passion.
So why isn't there a liquid tax-loss harvesting fund/ETF easily available to buy? The only one I can find involves buying into a whole portfolio other things and paying extra management fees.