LTSB and Cumulative Updates

As cumulative updates grow in size between release until they are rolled up in to the next release and the update size is effectively reset.  How does this apply to LTSB, particularly LTSB 2015, which was released without support for Express updates?  Will the size of the cumulative update grow every month for the lifecycle of the release?  If so, would we expect to see cumulative updates of approximately 10GB per month per client towards the end of that release cycle (10 years)?  Would building a new client with an old LTSB version require a full cumulative update including every patch for the previous 10 years to bring it up to date?