Sounds daft but we should measure the value of bitcoins in Big Macs or something like it. It would give a far clearer picture long term.
No. It should be the other way around. The prices of individual items change too much for a number of reasons and the price of individual items are different in different places of the world due to different costs for producing such goods.
You could potentially measure the value of bitcoin based on some kind of measure of CPI (eg purchasing power) however this is somewhat complex and would probably be difficult to understand for the average user