I dunno, would you rather have ARM technology owned by a US company or by a front for the Saudi sovereign wealth fund?
When you choose to include ARM technology in some of your products, then you will spend a lot of time and money for the implementation and you will need a long term availability of that technology, to be able to recover you costs and to give you time to switch to another technology, if desired.
Now any long-term commitment for providing any US-owned technology can no longer be believed, because precedents show that such commitments can be unilaterally canceled at any time, without an early enough warning.
only if you are not already under the thumb of the US gov't. Otherwise, it's a non-issue.
Softbank has a chainsaw prince as a main creditor. This is a very compelling reason to get cash in any way possible.
Softbank needs cash. sells ARM. not a good reason?