Let's not get complicated here.
I understand you are talking about subsitution, if Coke becomes too expansive I drink Pepsi lor. But shouldn't we be evaluating the effectiveness of CPI in measuring inflation and costs of living instead?
CPI basket consists of basic staple in our daily lives. We have very little alternative or none at all when it comes to housing, transport, sugar and flour. Wanton mee is not important lar.
When the CPI increases, I am very sure it will affact us in some ways.
you still don't get my point, do you
the main reason why the cpi is unreliable is because of the weights it uses
there is another thing called the gdp deflator, which is equally ridiculous, it uses final year weights. directly translating money and goods today to the goods of tomorrow , like in my car example.. using the goods of yesterday, or the goods of tomorrow are silly in both ways.
another much stronger and extreme example would be.. saying that laptops cost more than they did in the past. or laptops cost a lot less in the past than they did today. so? what can you do with the laptops of today? what can you do with the laptops of yesterday? similarly, if there is a new technology which enables laptops to be mass produced at $1 each, so? does it mean that from yesterday to today, there was massive deflation?
certainly when cpi increases there MAY be a loose link that actual inflation has increased too. but even then, the amount by which it increases by should be taken with a huge pile of salt. even if you do take a very very reliable bundle as a basis for comparison:
1) there is no guarantee that your bundle reflects the appropriate level of inflation happening, based on cpi values
2) who's to say that you can't take another equally reliable bundle? and what basis is there for comparison with other countries? america's staple might be bread and potatoes, singapore's staple might be rice. do you really think that taking a bundle of bread, rice and potatoes is going to be a solution? there is no solution to this.. and we could easily argue that the bread and potatoes pricing will affect americans a lot more, than singapore.. vice versa for rice.
last of all, inflation should not be seen as a huge evil.
take for example - xiao ming earns $10 per month today. his bundle of rice, flour and eggs costs $8. suddenly his hometown is hit by a plague, in desperation due to short supply of labour, the employers start paying him $50 per month to not run and stay and work and produce goods in their factories. due to shortages his bundle now costs $16. is xiao ming's standard of living, measured at face value, reduced even though there is massive inflation? he can purchase 3 bundles instead of the original single one. so his standard of living, ignoring the plague, could be said to be higher!
there are many other factors than epidemics that can cause such a scenario to happen, or other scenarios where the notion that high inflation is bad for the individual can be easily disproved and debunked.