Enterprises are sweating legacy IT assets as AI investment grows

Companies are getting more selective about replacing legacy kit such as mainframe systems, and rising AI investment is one of the factors causing them to hold onto these existing assets for longer.

Managed services biz Ensono claims in its 2026 State of IT Modernization report that 78 percent of IT decision makers regard legacy systems as more important today than they did two years ago, and this is because such systems are viewed as key to making AI work for their organization.

The report is based on a survey of 500 IT decision-makers and line-of-business leaders conducted by the firm across the US and UK.

Its findings show that AI is reshaping modernization priorities, but that corporates are still grappling with many of the challenges that have traditionally complicated modernization efforts, such as budget overruns, delayed initiatives, and talent shortages.

Ensono found that 45 percent of firms are actively scaling AI deployments across their organization, while 44 percent are investing in targeted, high-impact use cases.

Supporting AI, automation, and advanced data initiatives is now the top pressure driving modernization, while more than half of companies say that AI is helping advance modernization by delivering through greater automation and improved efficiency.

Among the barriers businesses face, the top challenges to achieving AI goals are said to be difficulty integrating AI into existing workflows and business processes (33 percent of respondents) and infrastructure limitations (28 percent).

For this reason, Ensono says that those legacy systems are taking on new strategic value as organizations attempt to scale their AI rollout.

Nearly half of organizations view legacy systems such as mainframes as a critical foundation for AI and an important source of data for this purpose, while 47 percent use them selectively for specific AI applications.

More than half of organizations are optimizing and extending legacy systems while modernizing applications where they are, rather than replacing them outright.

This is an approach that’s slightly more common in the UK (57 percent of respondents) than the US (48 percent).

“Enterprises are discovering that legacy systems, like the mainframe, are intensely powerful, reliable and efficient sources of computing that can now be augmented and made more agile thanks to AI,” says Ensono’s Chief Strategy Officer Brian Klingbeil.

“These systems contain decades of data and business logic that drive many companies.