The phrase "pivotal sector" is correct and can be used in written English.
It refers to a crucial or essential part of a larger system or industry. Example: The technology sector has become a pivotal sector in our modern economy, driving innovation and growth across various industries.
Early 20th century patrons established a precedent for private patronage to the arts that has since evolved into a pivotal economic sector in the United States.
Residential buildings contributed 14% of Canada's greenhouse gas emissions in 2014, making this sector pivotal to climate change mitigation.
The success – or not – of the diversified industrial sector is pivotal as it has an impact on the supply chain of so many other industries.
That Radio Hamburg happened to be in the English sector proved pivotal to the development of the German broadcasting network and its orchestras.
The Universities Australia chair, Professor Barney Glover, was due to tell the National Press Club in Canberra on Wednesday that greater investment in the sector was "pivotal" and the political impasse was "intolerable".
This is because the private sector is pivotal to the production of goods and services that is germane to the development process.
East Timor was a training ground for the officer corps in tactics of suppression for Aceh and Papua, and was pivotal in ensuring military sector dominance of Indonesia.
Widespread involvement across all industries and sectors is pivotal to the program's success.
A pivotal component of our manufacturing sector, with incalculable effects across the supply chain, is being shut.
The introduction of the Children Act 2004 was pivotal in bringing different public sector agencies together to provide integrated services for children in a variety of new settings.
