The power supply may or may not be used for 7 years, but the warranty and efficiency is still a good indicator of the quality of the power supply.

Also, I don't see why this person might not be using their power supply in 7 years time. Computer parts are getting more power efficient, rather than less, and a 550 watt power supply today will still be fine in 7 years unless there is a major change in the type of connections used, and, considering we still have VGA connections on monitors, graphics cards and motherboards, I don't think a current power supply will be completely obsolete in only seven years.

Processor and graphics card combination is decent, but I don't think there is much point in buying computer parts now when CES 2019 is so close, and AMD is likely to announce new CPUs and GPUs that might either give you better value for money, or drive down the prices of current parts.