It might depend on what country they're selling to. Maybe petrol is too cheap in America for it to matter much but it's a big deal where I live and fuel economy

It might depend on what country they're selling to. Maybe petrol is too cheap in America for it to matter much but it's a big deal where I live and fuel economy is a major selling point that people look for in cars, hence the popularity of hybrids despite them costing more up front than conventional cars.