Firstly, as it seems a few people missed this, Im going to write this a couple of times,
so everyone understands I wasnt being serious.
Now thats been cleared up.
On a global scale you're (possibly?*) losing purchasing power.
Would probably be better to compare gains in real terms after inflation in each country to see which investor would have gained the most wealth.
Its all a juggling act between several things, forex gains/losses do impact our pockets, so does inflation.
Examples
SA is a net importer, so wheat, petrol, etc costs more because of a weakening rand.
If we were net exporters like China, a weakening currency is supposedly a good thing (its debateable).
Singapore, economically very strong, economic growth and strong currency, so their house prices
have gone from $50,000 to $2.5million for the same house over 20 years. Thats what a strong economy does.
Finally you also get deflation which impacts everything. Japan has been going through deflation.
Deflation can improve the strength of a currency, but also has its negative side effects as well.
Inflation a house price will go from R 100,000 to R 1,000,000,
Deflation is the reverse where a house price goes from R 1,000,000 back to R 100,000
before you freak at that thought, think of this as well, costs do the same thing -
Price of cars can get less and less as well.
As you see its not so much one factor, which makes it all difficult.
You need to add inflation + growth + forex impact + ... + .... etc
Its really tough to consider it all, but if you evaluate individual investments and they are only
local based then I agree the best is probably looking at with Growth - Inflation.
And yes on a global basis, you are right, we lose purchasing power.