I'd say
115 million. But it'll have taken three more years to reach within 2 million of what PS4 managed in seven years. 115 million by 2030 is a high estimate IMHO. Depending on factors, other estimates could look like what follows:
>Limited sales promos, no permanent price cuts, less 3P exclusives, Day 1 PC for non-GAAS 1P AAA (by 2026-2027), PS6 2027 launch: 95 - 100 million
>Limited sales promos, no permanent price cuts, less 3P exclusives, Day 1 PC for non-GAAS 1P AAA (by 2026-2027), PS6 2028 launch: 100 - 108 million
>Limited sales promos, no permanent price cuts, less 3P exclusives, 6 months - 1 year stagger for non-GAAS 1P AAA (by 2025-2026), PS6 2027 launch: 98 - 102 million
>Limited sales promos, no permanent price cuts, less 3P exclusives, 6 months - 1 year stagger for non-GAAS 1P AAA (by 2025-2026), PS6 2028 launch: 104 - 110 million
>Limited sales promo, no permanent price cuts, less 3P exclusives, 6 months - 1 year stagger for non-GAAS 1P AAA (by 2026-2027), PS6 2027 launch: 100 - 104 million
>Limited sales promos, no permanent price cuts, less 3P exclusives, 6 months - 1 year stagger for non-GAAS 1P AAA (by 2027-2028), PS6 2028 launch: 105 - 115 million
Personally, I don't think SIE are going to prioritize permanent price cuts for PS5 until near the time PS6 launches. I also think we're going to see less 3P exclusives (timed and otherwise), so 2024 might just be the peak in terms of 3P exclusives we'll see for PS5, in terms of big AAA games like FF7 Rebirth, Rise of the Ronin, Stellar Blade & Granblue.
Sales promos will be "less", as in, specifically targeted in select markets, like we've been seeing a lot this year across parts of Europe. And I genuinely don't think SIE are going to reverse course on the multplatform strategy considering the likelihood this GAAS push of theirs goes belly-up. If the GAAS stuff doesn't work out, SIE will probably double-down on multiplatform ports of non-GAAS titles to PC (with shorter windows or Day 1) and GAAS to more platforms (i.e Helldivers 2 on Xbox), as well as more select non-GAAS ports to other platforms aside from PC (specifically Nintendo , hell maybe with ports of games like Astro Bot :/), to make up for what they'd of expected the GAAS initiative to bring in.
As for what PS5 could do by the time PS6 itself launches? Well, I think it'd get to 90% of above estimates for any scenario where PS6 is a late 2027 release, or 94% of above estimates for any where PS6 is late 2028. So something like
88.2 - 93.6 million lifetime in a 7-year timeframe or
97.76 - 108 million in an 8-year timeframe. So a worst case that's just slightly better than PS3 launch-aligned, and a best case ~ 10 million below PS4 launch-aligned. And, I do think increased competition will play a big factor combined with aforementioned choices on SIE's end, but that doesn't have to mean Xbox: Nintendo, Steam, and the ever-present mobile market will likely be PlayStation's biggest competitors going forward, even if they are not directly competing with it the way Xbox has in the past.
But I think a more interesting question is, supposing SIE continue their current strategy & accelerate it, what will early adoption rates for PS6 look like? Personally, I think they'd be below PS4 & PS5 by a decent margin. We're dealing with a PS6 that'll likely be more expensive on the low-end SKU vs. PS5, and could reach PS5 Pro pricing at the high-end SKU. Along with more cross-gen support, less 3P exclusives, and pretty much all their 1P games up to that point from 2020-onward being on PC and/or other platforms. I also kind of doubt PS6 would be bringing a lot to the experience front aside from yet prettier graphics and higher framerates, and still lacking in many of the features other platforms like Steam provide despite being free.
As things are I can't picture a PS6 breaking 12 million in the first year (compared with the 14 million PS4 & PS5 each did, PS5 being supply-constrained otherwise they'd of likely hit 17-18 million in its first year IMO).