5) wii ltd shipped (2007-12-31) - 20.14 million
5) ps4 ltd sell-through (2015-01-04) - 18.5 million
I'll try to explain why it is always relevant to note Wii numbers were shipped instead of sold to consumers.
Shipped - sold through =
in stock/transit.
Japan: 4.99 (dec.31) - 4.86 (jan.6) =
0.13 or 2.58%
North America: 8.85 (dec.31) - 8.19 (jan.5) =
0.66 or 7.46%
Others: 6.30 (dec.31) - ??? = ??? ???
(hardware units in millions)
Despite Wii always selling out, there's still a perceivable difference because goods transportation doesn't employ teleport (yet). It takes days (or even weeks) for a product to reach the consumer's hands.
Please note there already is one additional week in the numbers sold to consumers. If we remove that week to match the same date as the shipment, the number of units in stock/transit will be even higher (how much higher, I don't know due to the lack of weekly sales in North America)
Based on the information above and assuming every unit shipped to Others until Dec. 31/2007 was sold by Jan. 5/6 2008,
Wii sold through number cannot be higher than:
4.86 (jp) + 8.19 (na) + 6.30 (others) =
19.35 million.
But as I already explained, that assumption is unlikely to be true. The most probably scenario is that there's a percentage of the 6.3 million shipped to others still in stock/transit. What percentage?
If we use Japan as a base: 4.86 + 8.19 + (6.30 * (1 - 2.58/100)) = 19.19 million
If we use North America: 4.86 + 8.19 + (6.30 * (1 - 7.46/100)) = 18.88 million
But what is the actual number? How is the retail distribution system in "Others"? Does it have less surplus than Japan (since "Others" are a bunch of smaller countries)? Or is it has even more surplus than North America (4 countries vs. 20+)? Unfortunately, we don't have the answer.
And the same apply to software, except in even larger scale, since odds are the average game sits in a shelf for much longer than a console (especially one that was selling out like the Wii).
Shipped - sold through = in stock/transit.
Japan: 16.8 (dec.31) - 13.6 (dec.30) = 3.2 or 19%
North America: 60.9 (dec.31) - 34.9 (jan.5 - US only) = 26.0 or 43%
Others: 35.5 (dec.31) - ??? = ???
(software units in millions)
In conclusion, Wii shipped 4.32 million from Jan-Mar 2008 and was still selling out. There's no way the PS4 will match that. The PS4 will not be this close to the Wii total again at least until 2019.