Meaning of the word "jam tomorrow and jam yesterday, but never jam today" in English

What does "jam tomorrow and jam yesterday, but never jam today" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

jam tomorrow and jam yesterday, but never jam today

US /dʒæm təˈmɔːroʊ ænd dʒæm ˈjestərdeɪ bʌt ˈnevər dʒæm təˈdeɪ/
UK /dʒæm təˈmɒrəʊ ænd dʒæm ˈjestədeɪ bʌt ˈnevə dʒæm təˈdeɪ/
"jam tomorrow and jam yesterday, but never jam today" picture

Idiom

used to describe a situation where pleasant things are promised for the future but never actually happen

Example:
The government keeps promising tax cuts, but it's always jam tomorrow and jam yesterday, but never jam today.
The workers were tired of being told there would be jam tomorrow and jam yesterday, but never jam today regarding their bonuses.