Even more reason to say "we can't deliver X because it'll cost Y and our budget won't allow for that" rather than "we'll pretend X actually costs Y/10 and defer

Even more reason to say "we can't deliver X because it'll cost Y and our budget won't allow for that" rather than "we'll pretend X actually costs Y/10 and defer the inevitable problem". Then politicians in the first year will consider that you have delivered X for a fraction of its actual cost, and thus setting the entire service up for failure in the future.