The difference is that Scala devs didn&#x27;t push for immediate adoption while they were still working things out.<p>Apple&#x27;s Swift message is more or less &quot;Stop writing Objective-C if you can and start using Swift – oh and by the way – you will have to rewrite your code with every major Swift release which we will be releasing at a rapid schedule&quot;.<p>It will be very hard for Swift to get rid of all the cruft they accumulate.<p>In Scala every major release addresses one or two pain points and migration is very smooth – no &quot;rewrite all your stuff&quot;.