Of those 30% of PS5 owners who never had a PS4, I wonder how many had an XB One or Series prior?

I can only think of Sony trying to fully use their production lines to build up a small buffer at retailers for when they have to retool their lines to make them ready for the new PS5 model.
I can't imagine that retailers will be able to sell all those units to consumers in the rather slow beginning months of the year.

With this level of production capacity, we can expect retailers all around the world to be fully stocked by the end of March.

I found some incomplete but quite substantial official quarterly hardware data for PSP and PS3. https://web.archive.org/web/20130927211956/http://www.scei.co.jp/corporate/data/bizdataps3_sale_e.html

I think there might be some charts on the site that show the fastest-selling consoles, but you also have to compare that rate for different milestones. I'm pretty sure PS5 is one of the fastest to reach 30 million.
DS (a handheld console) already hit 100 million by March 2009, and Switch hit 100 million plus by March 2022. Wii hit 50 million by March 2009, which meant the sales were very front-loaded. After 2010, Wii sales were quite negligible compared to before.

By sales PS5 took the win for 10 million*. Then I think Wii is number 1 up to about 55 million then DS is the quickest for any milestone up to it's lifetime total (then PS2 for anything above DS total)

*at least for hardware from 2004 onwards, as GBA had an explosive start so may have reached 10 million faster, but we dont have sales and Nintendo only reported shipment figures every 6 months at the time.

For the 30 million milestone I haven't checked it to confirm for sure but believe it will be: Wii > GBA* > Switch > PS4 > DS > PS5 > 3DS > PS2* > PSP > PS3 > X360
(* GBA & PS2 are based on shipments)

The 6.2 million FQ4 (CQ1) is substantial and should be doubted for obvious reasons but if the PS5 is going to make up ground or even surpass the PS4 next fiscal year it will be absolutely necessary to obtain some record quarterly sales. So good luck team PlayStation. We are rooting for you. The people want to see it!

If PS5 can reach 19 million this fiscal year then it will beat PS2 and PS4's second full year and just be behind PS1's.

* Q4 remaining, forecast to ship 19 million

Hardware shipments After 9 Quarters

Wii - 44.96 million
PS4 - 37.80 million
DS - 35.61 million
NSW - 34.74 million
GBA - 33.81 million
PS5 - 32.10 million
3DS - 31.09 million
PS1 - 29.50 million est. (32.82 million after 10 quarters)
PS2 - 28.68 million
PSP - 22.30 million
PS3 - 21.10 million
N64 - 17 million est. (15.22 million after 8 quarters)
GCN - 13.5 million est. (14.57 million after 10 quarters)
Wii U - 6.68 million