I strongly disagree with the premise that inflation should not be of material concern to retirees.
There are too many expenses over which either (i) we have no control or (ii) we can only control by lowering our standard of living:
1. health care
2. food
3. rates (aka property taxes) - just increased by 10% here in HK
4. home repairs and maintenance (if you own a home)
5. rent (if you do not own a home)
6. utilities
7. transport
8. holidays (doing without a holiday is not avoiding the impact of inflation, it is lowering my lifestyle because of it)
And for some early retirees
9. education costs for children (an estimated 18 years worth in my case)
10. mortgage interest (most of the of world uses floating or short term fixed rates rather than long term fixed rates as in the US and at least some retirees do carry mortgages into retirement - possibly including myself)
Wage inflation in is very real accross Asia (especially in China and India which have a combined population which of about 7x that of the US). That wage inflation is going to translate into (i) higher production costs which will eventually be reflected in higher selling prices for many goods and (ii) higher demand which will make it unlikely that competition will keep prices down. Inflation in the 4%+ range is already here for a number of developed and developing markets - UK, HK, South Korea to name a few - and non-discretionary items such as food, transport, housing (ex UK) and health care are all big contributors.
Global demand for energy and food is still rising and is expected to continue rising as the developing world catches up to the developed world in terms of incomes, living standards and consumption. Unless supply grows even quicker, rising prices will follow. If prices of basic necessities keep going up, then wages will follow - if for no better reason than to suppress civil unrest.
Things may be a little different in countries suffering from recession, but (i) most food and energy prices are set globally and (ii) currencies of the countries in recession would normally be expected to be weaker than those which are still growing. While this is not always true (e.g. Vietnam), where it is true, it points to a higher cost of living.
I put 4% inflation into FIRECalc (instead of the lower default) and saw my success rate drop noticably. At 5% it was telling me I shouldn't retire.
Inflation matters.