People aged 65 to 75 accessing a video streaming service has jumped to 57% from 36% a year ago, the consultant said.
Adoption of new technology by the elderly has also been speeding up said Deloitte with more than 19mln devices bought in the year to July or 8% more than a year earlier.
Some 35% of respondents added they might even do without the terrestrial TV channels within the next three years.
Paul Lee, a partner at Deloitte, said: “The pace of adoption has been really fast. It has been a surge, due to lockdowns, in particular during winter. One of the easiest things for relatives to do to make sure they are okay is to set them up with a video subscription.
“I would still expect the majority of consumption in this group to be in broadcast, but there will be some people switching mostly to on-demand.”
Netflix and Amazon have started to switch the focus of some content to tailor to older audiences as near-saturation point approaches among the traditional core of younger viewers.
Helen Rees, director of media at Deloitte, said: “Streaming subscription growth is slowing among every age group other than those aged over 65, offering a new and loyal audience for platforms to target.
“This should be a clear focus for streaming platforms in the year ahead as they look to set themselves apart in a crowded market. Platforms that invest in quality content and stories that strike a chord with older audiences will reap the rewards.”