Because the new budget phones are designed/optimised with KitKat in mind with a lot less functions and bloat, whereas the S3 Mini released nearly two years ago was built with 4.1 Jellybean in mind. As I said they probably could create a 4.4.2 update, but it would be work they are not willing to do for what what they would probably consider a minority.
Plus after looking at Samsung latest advert they would rather you updated to a new device, rather than update the older models.
http://www.360nobs.com/2014/07/samsung-tells-you-why-you-should-ditch-your-galaxy-s3-for-a-galaxy-s5-video/
That's the most stupidest thing I have ever seen!
1.Why would Samsung compare their own products?
2. Why would you ditch a perfectly operational and capable S3 for more features that S3 could offer just as well as S5?
3. Throwing away phones are harmful for the environment and on top of all that Samsung is encouraging it!
Our S3 Mini is capable of handling KitKat, no doubt. BUT without source codes from STE, who just adandoned us like street dogs , it's very very hard to make an official update coming from Samsung. @mclaw has an awesome ROM, but it's vanilla android, not Samsung android. Plus it has some minor and not so minor bugs that need fixing. In other words, Samsung did try to upgrade our phones, but just couldn't succeed, because of STE (idiots). Also the VE has a Qualcomm processor, which is clocked at 1.2GHZ and is better than NovaThor (even if both were 1GHZ, Qualcomm would still be better). That's why for Christmas I'm buying an S5, upgrading it to Android L (ollipop), because the update WILL come to a flagship phone and am just gonna live a few years of my life without worrying about updates, lag, battery life or handy features
But then what about the original S3?