unusually high capital gains ... has ... drawn scrutiny from regulatorsdebate over whether target-date funds are suitable for taxable accountsThe high Vanguard distributions were the result of a technical change Vanguard made. It lowered the min for institutional funds, thus triggering a mass selloff by small company plans as they migrated from retail clones into the institutional funds.
Once one realizes this, the two statements above come off as a nonsequitor.
Suppose that instead of target date funds, Vanguard had lowered the min of VITPX from $
100M to $5M. (For the sake of argument, assume VITNX, VSMPX, and VITSX did not exist.) One would expect to see a similar migration of small employer plans from the retail fund VTSAX to the institutional clone VITPX.
This in turn could trigger a large cap gain distribution to the remaining retail investors. VTSAX has unrealized cap gains amounting to about half of the fund assets,
according to M*.
Surely one would not suggest that a total stock market fund was an inappropriate choice for a taxable account, just because a poorly planned change could could trigger a torrent of recognized cap gains.
This is a completely different question from whether target date funds are suitable for a taxable account.