Hi Fooanon,
For your information 5M570ZT144C5N is still active and available. Anyhow, the life cycle is depending on its order volume. Hence, we do not have the estimated EOL.
For the discontinued FPGA and CPLD, you can always refer to Product Discontinuance Notices (PDN) through this link: (Intel® FPGA PCNs, PDNs, and ADVs) If the Ordering Part Number does not have any PDN available, the part is still active and available.
You can subscribe to our customer notification mailing list at below link so that you can be notified when an Altera(now Intel) device is going to be discontinued.
https://www.intel.com/content/www/us/en/support/programmable/articles/000080707.html
Regards,
Fakhrul