Not overlooked, just no causal link made. You have associated the continued improvements with the economic system pursued for the last 40 years. The benefits from improvements in health, technology, communications and medicine pre-date trickle down economics by decades if not centuries.
Rome will never fall.
http://www.telegraph.co.uk/finance/economics/10417838/Harsh-truths-about-the-decline-of-Britain.html
https://www.ft.com/content/d56b46f6-b237-11e6-9c37-5787335499a0
Trickle down economics has been pursued in Western economies for the last four decades and the gap between rich and poor has continued to grow. Despite taxes being kept low, businesses have still moved their production to other countries because the job of their directors is to maximise profits...
A quick Google tells me that the 'private business' to which you refer received £4.8 billion in public subsidies in 2015/16.
http://www.orr.gov.uk/__data/assets/pdf_file/0005/22982/rail-finance-statistical-release-2015-16.pdf
Given that they spent £200 million of the £4 billion they received...