Personally, I'm of the opinion of the commenter above you—automating most software jobs will require strong AI. Replacement of those might happen someday, but it's sufficiently far away to not think about as an imminent threat to your job (though I agree we should be doing high-level planning about how as a society we will cope with strong AI).
Better tools allow us to do more, faster etc. Thing is amount of things software can do that it is not doing yet is absolutely immense and ML only opens more and more of it.
I think any actual reduction is so far in the future we have no concept of when that will happen and how.
I mean a am I huge proponent of self driving car.. when is that coming? When it works it will absolutely change economy as massive amount of people are now involved or depend on those that are.
Software is an arms race. You need new software if your competitors are writing new software, but any organisation can coast for a long time on its “legacy systems”. That’s what we saw after the dotcom crash. If there is a prolonged economic downturn and the software industry just goes into maintenance mode, it will be very, very unlike anyone who wasn’t there last time will understand.
Sure there will probably always be a few programmers, but as tools (and soon I expect AI) gets better those programmers can do more and more of the work. I wouldn't be at all surprised to find the number of software engineers decreasing in the not too distant future.
The only reason it hasn't already is that we've managed to grow the number of things software developers are doing at the same rate as the increase in number of software developers * the increase in efficiency per software developer. And in some parts of software development (e.g. games) it has.