I've never been a fan of the use of the term "minnow" TBH. Clearly there will always be certain teams that are stronger than others, but some new teams could easily have been, relatively speaking, stronger than some established ones at other times, but the established team won't be called a "minnow" because it's... well, established.
For me there is one barometer - a team is Test-standard, or it is not. The overwhelming majority of teams granted Test status have been Test-standard; the only exceptions are Bangladesh (who have yet to reach it), New Zealand up to 1960/61, and South Africa up to 1905/06 (and many of their games were classified Test only retrospectively anyway). Zimbabwe, due to the deteriorating political situation, went from being Test (and ODI) standard to not being, in early-2003 - to date a unique occurrance.
But there is no way India of the 1930s or Sri Lanka of the early-1980s or Zimbabwe of the 1990s were as weak, relatively speaking, as England were 1986-1989; or Australia 1984-1988/89; or West Indies in 2007.
The strength of a team is what is important, not how long it's been playing for. Once a team is Test standard, no-one has any business in my book to be saying "well if you remove ... team from the equation then..." Only with substandard teams is it sensible to do that.
RIP Fardin Qayyumi (AKA "cricket player"; "Bob"), 1/11/1990-15/4/2006