Confusion around Winter Tyres

Every year I wonder when to mount the Winter Tyres to my everyday car. There are confusing messages out there and even experts seem not to agree on all the aspects. Rarely when ever can you see full comparisons of capabilities of summer and winter tyres under different conditions. What I have seen so far would indicate the following:
(a) In dry conditions even at low temperatures summer tyres outperform winter tyres (i.e. breaking, acceleration), despite the softer compound of the winter tyres.
(b) in wet conditions there's a temperature threshold at around 7 to 10 degrees celsius where winter tyres become superior to summer tyres.
c) if it's snowing or frozen then winter tyres always win

So, that would tell me that if I never drive under wet or snow conditions I could stick with the summer tyres. As you can't predict the weather this is not really an option. But for all my cars that I only drive in dry and salt free conditions I can drive them during summer and winter without needing winter tyres. If anybody has something to add to this assessment, please don't hesitate as I am eager to learn.