I guess there isn't a direct relation between the version number and the EOL.
(I know we can discuss about SemVer but I guess this isn't the goal here).
Since I can't find official communciation about this I will share what I think will happen. Magento 1 will be suported until the EOL with patches and fixes to ensure those stores can continue working and being secures.
But I can't imagine a new version with new features (at least that having PHP7 support can be considered as a new feature and not a patch).
Again, this is just what I understand will happen but isn't an official answer.
(My 2 cents)
Hi,I am also new here,I wonder if there is an easy way to upgrade 1x to 2x,my developer told me it almost =rebuild my store.....
Well... you developer was right. Upgrade isn't the correct word.
Is more a re-platform and yes, there will be several things you will need to build again (it will depend on which modules do you have now and which modules/services you'll need then)
For those of you that want to continue running Magento 1 beyond 2020, there's the community initiative to make a long-term-support version @ https://github.com/openmage/magento-lts
It contains even more fixes than Magento themselves care to implement because of Magento 2.
Hi, My Site is Currently running in Magento 1.9. I have a query. Incase If I didn't upgrade to Magento 2 Will my Site Stops Working? Can I have a live version without any security updates? Will It affects my websites security?
Your site will be keep running but it won't receive security updates from Magento. To be secure you should be on latest version of Magento or your site should be fully patched.
Till June 2020 Magento will support 1x versions.