I honestly think from a business perspective it may make more sense to wait it out as long as possible.

You will have to pay the cost at some point, but you only want to pay it once. If you wait it out, you'll get to use the tools and such that are available when you port, and also make a more informed business decision, since you'll have more information to work with 2 years from now than you do today.

Let's say you port all your code on a perfectly functional system today, then tomorrow an update to the library you used comes out, that had you used that version you would have saved 2 million dollars, or something like that.

Or maybe in 2 years it will just be better to switch the entire thing over to GO, or Javascript.

There's really no point in rushing to switch from a business perspective. Wait it out. You aren't losing anything as long as you give yourself a runway to switch over before end of life, which will depend on the project.

The developer in me says switch over ASAP, but the Project Manager in me says hold up until you need to switch.