Do you have some more specific pointers on how times have changed? I see eg. VFWAX (All-World ex-US Index Fund) but its expense and tax cost ratios are pretty similar to the international funds that are more localized.
The discussion you posted mentions that simpler is just as good, but doesn't make any real arguments why more funds is worse. The way I see it, if the various international funds I have turn out to be tightly correlated, then no rebalancing will happen and it will be similar to owning a larger index. If they are less correlated, then rebalancing does happen and it should lower overall risk.
In the old days when some books by Bernstein, Ferri, Swedroe were written and when the likes of Merriman, Armstrong, etc, started their web sites, …
VTIAX/VGTSX(total int'l) was a fund of funds which did not allow the foreign tax credit to be taken, so folks needed to hold the individual funds in order to get that important tax break. No small caps were included in the holdings as well, so it was a large-cap fund.
There was VTMGX which was tax-managed international which had a 5-year early redemption fee of 1%, so that made it less desirable for tax-loss harvesting, so some folks avoided it. This fund was large-cap developed and did not have emerging markets.
So one had to own the Europe, Pacific, and Emerging markets funds separately to get the tax breaks, avoid the redemption fees, etc.
Then VFWIX/VFWAX/VEU was started which was not a fund of funds. It made a good tax-loss harvesting partner for VGTSX and VTMGX. The ETF share class of VTMGX was added and the 5-year early redemption fee was removed.
It was hard to get small-caps in a foreign fund, too.This was when small cap foreign was doing great. DFA had such funds, Fidelity added new ones, other companies had expensive ones (MIDAX for instance). Vanguard did not have a small-cap foreign fund until the actively-managed VINEX was started in 1996, but I think it was closed to new investors for a time, too. Then in 2009 Vanguard opened VFSVX/VSS which is the small-cap version of VFWAX/VEU. This may have been the first index fund to hold small-cap emerging markets although DFA had had a passively-managed small-cap EM fund for a while.
A little later, the fund-of-funds nature of VTIAX/VGTSX was changed and the tax laws were changed so fund of funds could make use of the foreign tax credit. Also the fund changed the index that it followed and added small-caps, too.
Overlayed on all the above was the introduction of Vanguard ETFs. Most recently the ETF share class of VTIAX/VGTSX became available: VXUS.
More ETFs from other vendors have appeared, too. In particular, the small-cap foreign developed and emerging markets have several to choose from that didn't exist 10 years ago, such as SCZ, DLS, GWX, DGS, EWX, EEMS, etc.
So when Merriman was telling everyone about following Fama & French and DFA was ascendent, all those Vanguard funds didn't even exist in their current form, but the separate Europe, Pacific, Emerging funds did, so that's what got recommended.
Sure, one can keep them separate if one wants, but every once in a while an index changes and the more narrow fund has to sell the country leaving the index. For instance, I think South Korea and maybe Taiwan have switched from Emerging to Developed. Morningstar and Vanguard have a different list of countries for Emerging and Developed. I am not sure how index providers (FTSE, MSCI, Russell, etc.) divides up developed versus developing nowadays.
Folks also debate if the small-cap and value premiums exist anymore. Also debated are whether emerging markets has decent risk-adjusted rewards as it appeared to have in the past. Certainly the 3-year return of VEMAX/VWO is pretty bad at about 4% a year.
OK, that's some history and why I wrote Times Have Changed.