What's happened to train seats?

Modern train seats are hideously uncomfortable. So much so that the Rail Safety and Standards Board had to conduct a survey on comfort. But why are they so bad, and what can be done to improve them? Discord:   / discord   Credits: PeterSkuce, Geof Sheppard, RM, Bananaman28, Superalbs, Dani8ear and Smiley.toerist, CC BY-SA 4.0 https://creativecommons.org/licenses/..., via Wikimedia Commons Original artist unrecorded, Henry Pyall, A.B. Clayton, Peter Skuce and Snow storm in Eastern Asia, Public domain, via Wikimedia Commons UAV XTC, CC BY 3.0 https://creativecommons.org/licenses/..., via Wikimedia Commons Ben Brooksbank / Northward at Peterborough North, with a B1 4-6-0 on empty stock Dave Hitchborne / Railway Station, Carlisle James Petts from London, England, Hugh Llewelyn, Capt' Gorgeous, Elliott Brown from Birmingham, United Kingdom, Torsten Maue from Magdeburg, Deutschland, Marathon and David Hillas, CC BY-SA 2.0 https://creativecommons.org/licenses/..., via Wikimedia Commons Ashley Dace / Mark 1 coach at Sheringham Wrexham Bidston RUA Hull Trains DGE Cabinet Office, OGL 3 http://www.nationalarchives.gov.uk/do..., via Wikimedia Commons Dave Letorey from London, United Kingdom, CC0, via Wikimedia Commons RSSB Public Attitudes Toward Train Services - DfT Music: Cooper Ave - The Westerlies