Re: I expect down votes...
Microsoft will bin .Net Core one day, you can be sure of that.
This is a vapid observation. As you implied yourself, no product line will last forever. The question for developers is whether .Net Core is likely to last as long as their application. Frankly, that's hard to say for anything with a reasonably lifetime, as Microsoft's abandonment of Silverlight, WCF, etc show. I'm not making any judgement about whether those technologies were worth preserving or indeed using in the first place - just pointing out that Microsoft hasn't shown much commitment to the developers it encouraged to use them.
On the other hand, there were plenty of people who were dubious - with good reason - about Windows NT when it first appeared on the scene, and plenty of vendors who've been able to sell software on that platform for a quarter century.
As in most domains, making predictions in this domain is a fool's game. There's value in assuming that a platform might become obsolescent long before you're done with it, and planning based on that. But there's also value in giving customers what they're asking for, even if it requires using a dubious platform; and there's value in getting to market quickly, and in making use of widely-available labor, and so on.