Can GDP per capita be used to measure human development instead of the HDI?
No. GDP per capita only reflects average national income. It tells nothing of how that income is distributed or how that income is spent – whether on universal health, education or military expenditure. Comparing rankings on GDP per capita and the HDI can reveal much about the results of national policy choices. For example, a country with a very high GDP per capita such as Kuwait, who has a relatively low level of educational attainment, can have a lower HDI rank than, say, Uruguay, who has roughly half the GDP per capita of Kuwait.
