there is just too many drivers for everyone to be as deservedly appreciated as they should be..
people can only remember the best ones, otherwise you would have to remember almost everyone. who remembers hakkinen today? even he had great speed and was on par with the best drivers. etc etc.
in 20 years ppl will remember hamilton, vettel but wont remember rosberg. thats just how it is.
Hakkinen was a weird driver, he was slower than Coulthard up until 1998 when Newey started to design for Mclaren. He is one of those drivers that really fit with the design of the car, had Mclaren been more stable he would have maybe been a 4 time champion. Same with Kimi.
He is rated just right, had he been on Senna's and Prost's level he would not have lost 3 world championships, one of them being the main driver for Williams with all support in the world and still losing to Piquet.