don't see the logic in this advice.
first of all, majority of "newcomer domainers" are not developers of websites.
and how many websites a skilled developer can produce, shouldn't be thwarted.
that's a decision for each individual to undertake, based on their motivation, capital, ideas and other projects they may already have on the table.
as, if one is or has "developer" skills, then if they make more than 1 website....that's not putting all eggs in one basket.
10 sites can produce 2 winners that can provide income to produce more websites
as opposed to making only 1 website and depending on single source for revenue.
additionally, warren buffet has goo-gobs of businesses which he runs quite successfully, so don't see how that applies.
it's like saying, only focus on 1 domain at a time.
concentration and experimentations are givens and a plan is a must for any venture, however the suggestions are confusing because it's like you're trying lump newbie domainers in with website developers and the two are not the same.
imo....
