That's not how the chart suggested in Japan.
They sold out all the units of PS5 and Xbox they had for Japan. They didn't sell more due to lack of enough supply because they were releasing this time in more countries, so even if Sony and MS shipped more units in a worldwide scale than they ever did, there were less units available per country -most likely almost everywhere- than before.
Sony expects to outsell with PS5 this fiscal year that ends in March in a worldwide scale the amount of units they sold with PS4 in the same period. Which means PS5 is going to have the best launch ever for a console in gaming history.
And looking at the amount of big exclusives announced in PS5 and Series X|S for 2021, and comparing them to the exclusives PS4 and XBO had its first year, I think that at the end of 2021 PS5 will continue outselling PS4 launch aligned worldwide, and the difference with Xbox I think will be bigger than was back then. Specially if multiplatform games continue performing frequently very similarly or with a lead on PS5 in terms of performance and loading.
Regarding Japan, it's a small market for both MS and Sony, whose main markets are NA and EU.
Sony's market share is shrinking in Japan and it's going to be more competitive in this generation in the US as XBS and Nintendo Switch are the main competitors instead of WiiU and XBO in the previous generation.
My prediction for this Gen sales in the US and Japan.
US
NSW - 50M
XBS - 35M
PS5 - 30M
Japan
NSW - 30M
PS5 - 6.5M
XBS - 300K
Outside the covid bump of Q1 & Q2, PS4 was outselling Switch launch aligned due to having an extra Q3, so they have pretty similar sales. But there's a difference regarding their sales curve: PS home consoles are in the market during ~10-12 years, while Wii and the portables are during ~8 years and Nintendo home consoles outside Wii last ~6 years.
This means PS4 will pretty likely outsell Switch in the long run once all is set in stone after their full lifecycle. And PS4 is outselling PS2 launch aligned.
And PS5 seems will outsell PS4 launch aligned during at least the first year.