Maybe we should limit these smaller, lighter lenses to 1500 grams which easily covers the three lighter Nikkor lenses I’m thinking about. The 400/4.5, 300 PF, and the 500/5.6 F mount PF.
I guess that might be one of the marketing exercises they undergo.
Imagine a couple of developers and the marketing people sitting together preparing the two or three lenses they'd like to build next to the head of lens/camera devision fighting for the budget they need for execution.
They surely have different value prepositions and technical darfst they could achieve and maybe one or two mockups to illustrate the look and feel of the lenses they target.
Ultimately the brand philosophy and last but not least the achievable revenue in conjunction with manufacturing capacity and capabilities will be discussed.
Sony has NO pedigree in wildlife photography or sports and action yet. Yes - their cameras opt for these areas as well but a classic 500 f/4.0 would neither fit their targets being light and nimble nor would it be a huge selling success costing as much as their GM 400 and 600 lenses being in the middle with no extra advantage except being maybe 300 g lighter.
Therefore I think Sony will address a area that's more like a wider market for many photo enthusiasts.
What's missing is a fast 200 .. 300 mm prime and an ultra lightweight tele macro and similarly something like the new Nikkor 400 f/4.5
SONY could do all of these lenses but they must meet a broader audience to generate lots of revenue. Either it will be an expensive exotic prime for a top end market or they'd go for a wider audience with a mediocre pricing range but huge volumes.
Talking about huge volumes in a chip shortage sounds like a contradiction in itself.
Nevertheless we can be sure Sony will follow it's brand pillars for compact lightweight fast and optical outstanding solutions,
What we know from the outside is the gaps in their portfolio and these are mainly in medium fast primes. The top notch and top end is served perfectly for the few who are willing to spend that amount of money because they can or want.
For me an € 14 k lens is absolutely feasible but having owned the EF 300 L IS USM II f/2.8 I can tell you it's a pure waste of money owning such a lens when it's too heavy for an all day hike sitting on the shelf collecting dust - I will never ever again buy a 3 kg monster that's purely a trunk filler in my car - never carried it for more than 1 .. 2 h a day. That's not a walk about lens weight for me. Therefore I don't think we'll see any 2 ½ kg 500 f/4.0
Nikon has shown that it can be easily done to fit a quite similar lens in 400 mm f/4.5 at less than 1.3 kg
In case Sony makes one of these lenses it will be probably a lightweight option IMHO
With the latest Sony design technology, it could weight around 2,500 g. For me such 500/4.0 is the best balance between reach and weight/size. I miss this lens after sold Canon EF 500L/4.0 IS that weighted at 8.5 lb or 3,870 g.
