Lannie has gone to bed, but I am back for a couple hours before the pillow yells my name ("Come to bed ya stoopid oldt phart!"). Anyhoo...
Yes, I fully believe the 18650s will be around forever, but
will the higher Amp types be available? The standard 18650s that are used in LED flashlights don't have the power (or the safety) to be used in a mod -- unless you don't mind a burned face now and then.

And, believe it or not, we do understand that the iStick30, iStickTC40, X6s, EVODs, Disrupters, and the other shinies we have that use proprietary batteries might go away and not be replaceable after the Communist Federal Statists get done with us, but they have a finite life anyway. For example, the iStick30 is likely to last for only 300 recharges (about a year from date of first use if you vape over 10W), and given that the battery is inseparable from the electronics, when the day comes that it will no longer hold a charge, the whole thing goes in the garbage pit (after I have extracted select parts).

I have a preference for regulated mods, but they can be obtained with replaceable batteries (such as 18650). So we are (as we can afford it or win it) acquiring mods like the iJoy, Koopor Plus, SXmini (why do they call it "mini" when it is large and weighs a ton? I call mine "Thor's Hammer" because you could use it to knock out a Grizzly.), etc. We have also bought some K-boxes to keep on the shelf for emergency purposes. And we are looking at (studying) unregulated (mech) mods for additional backups, simply because they are not stuffed full of proprietary surface-mount electronics (extremely hard or impossible for the "average" home technician to repair) and just about anyone can build one out of parts scavenged from other broken mods. Does all that make sense?