Everybody focuses on the rumour about a smaller phone in 2020 and totally ignores what's rumoured to be coming out this year. If the people want a smaller phone, then why not just make it now. I guess they need to get a little more life and $ from the current versions before moving on to new (old?) things.
I think Apple faces a significant challenge getting the necessary sized battery into a smaller form factor, and that's the biggest holdup to a smaller phone of an SE size.