Maintaining an IT function requires serious capital investment. Tax depreciable asset registers can grow significantly as a result and can be difficult and costly in terms of time and money to maintain and update. The high cost is also a barrier for new businesses, which would likely prefer to spend funds raised on actively pursuing the business venture.
Existing large businesses are more likely to progressively shift to private clouds, such as running their own inhouse cloud for security. Large corporates are less likely to move to external clouds until they are confident that security, privacy and other legal issues are unlikely to be problems in either the immediate or long term.
A shift to the cloud means moving from maintaining your own capital-intensive IT infrastructure, to operational service-based expenditure for day-to-day running by third party specialists. From a tax perspective, the benefits could include cost savings resulting from the shift from capital expenditure deductible over time to expenditure on revenue account.