Sony is a great company for which I have a huge admiration. For many reasons I won't describe here.
It is also a company that has taken very clear decisions in terms of autonomy, responsibility and profitability of their different business units. They know they can't have it both ways.
In a world where imaging sensors are quickly becoming a commodity, volumes and cash flow are more than ever important to generate the revenue needed to stay ahead considering the huge cost of R&D and manufacturing units.
So breaking the relationship with your largest customer in the high end sensors segment wouldn't make much sense at all, would it?
Depends what level the move is planned at.
It's no different to planning at any other large organisation - a government or a military force, for example.
Some things are planned and executed at low level - the level of a single branch of a government department, or at company or battalion level, or at the level of a single store or local office of a corporation. These will be in pursuit of overall goals from above, but will not be directed or planned from above (often being local and opportunistic), although they may obtain support from above if the higher levels see it worthwhile to invest in it. This may be anything from hiring new staff in order to open a new ward at a single hospital, planning an attack to capture a bunker in a sector allocated to the battalion or organising a local promotion or sale at one store to take advantage of a local festival. Support from above may be financial (giving the hospital more funds to pursue its goal), logistical (allocating more fuel and ammunition to the battalion, or diverting more stock to the store) or direct (allocating temporary staff to the hospital or store to support the move, or providing support from divisional- or corps-level artillery for the attack). Or it may not be present at all and be a purely local effort. In either case, the planning and execution of the operation take place entirely at that level, without explicit orders from higher up. These operations may advance the organisation as a whole, or they may just make life easier for the local or low-level branch.
Some things are planned and executed at a higher level - a government department, at division, corps or army level in a military force or at the level of a single company within a multinational conglomerate. A transport department may decide to prioritise rail instead of road, hurting the subsidiary freeways department but fulfilling their goal of moving more people. A hard-pressed division may leave a battalion to hold the line while it retreats - the battalion is all but certain to be wiped out, but its sacrifice allows the division, and others, to survive. A company may decide to close down a store, or even a chain of stores selling one range of its products, which is either no longer profitable or whose resources could be better allocated elsewhere - it may hurt the store, but help the company as a whole.
And some things are planned and executed at the very highest levels - an entire government, a theatre of battle or even an entire military force (which may consist of multiple allied forces) or at the level of an entire multinational corporation. This may be something like slashing the education budget to pay for further investment elsewhere, withholding resources (both personnel and fuel/ammunition) to a particular theatre in order to attack harder, or blunt an enemy attack, in another, or getting your sensor division to stop selling sensors to the rival you're trying to take over, now that your camera division has a product that's competitive with your rival's products and could use those sensors (and the rival's lack of said sensors) to take the rival down a peg and potentially leave them vulnerable to a takeover. Each of these moves will hurt some of their subsidiaries - the education department which has had its budget slashed, the army group which has to give up offensive operations, or even withdraw from a sector, the division which is certain to suffer heavy casualties in the initial attack or the subsidiary company which has to give up some of its sales - but, ultimately, serves the purpose of the organisation as a whole.
And there are many more levels between these. All of them involve doing things that hurt certain subsidiaries, but, ultimately, advance the goals of the organisation as a whole. Just like sacrificial pawns in chess. Constantly attacking everywhere, with little coordination between individual elements and no overall strategy, is no way to win.