Not true anymore. A lot of modern games are making use of more than 4 GB now, even at 1080p and 1440p. For example, with Red Dead Redemption 2, you can turn up texture quality to Ultra without much hit to performance if you have an 8 GB card, which makes the game look amazing, but you need to turn down texture quality on 4 GB cards. And anything less than Ultra texture quality in RDR2 looks significantly worse.
Just look at this comparison between a 4 GB GTX 1060 and an 8 GB GTX 1060 that was done a couple years ago. The 4 GB card skips and lags in every game. And the GTX 1060 is very similar in performance to the 5500M, so this isn’t some ultra high res 4K gaming comparison that won’t apply. These tests are at 1080p.
This is a test of 4GB vs 8GB of system ram. Of course the game is going to lag with only 4GB of ram. The video card being used is GTX 1060 6GB card, which only came in 3GB and 6GB variants.