Honestly, sales were low for a long time before they changed... God knows.

I wouldn't say 'horrendous' but the designs were very 2005 even though it was 2015. And some people liked the chunkier platform to hold on to - Xperia has always had a core market that liked the security of a well-built, easily-gripped handset as well as Sony's audio software.

My housemate has never owned another brand of smartphone. Ever.
My cousin is almost the same. Almost always an Xperia.