It's not a well-known one, but we have.

• 親【おや】苦【く】、子【こ】楽【らく】、孫【まご】乞食【こじき】 "Parents toil, children ease, grandchildren beg."

Also with many variations:

• 祖父【じじ】は辛労【しんろう】、子は楽、孫は乞食
• 「親苦労、子楽、孫ほいと」「親苦労、子楽、孫潰」「親苦労、子楽、孫貧乏」 etc.
• 親‌草鞋【わらじ】、倅【せがれ】草履【ぞうり】で、孫‌雪駄【せった】、曾孫【ひまご】の代には裸足【はだし】なりけり

It's not a well-known one, but we have.

• 親【おや】苦【く】、子【こ】楽【らく】、孫【まご】乞食【こじき】 "Parents toil, children ease, grandchildren beg."

Also with many variations:

• 祖父【じじ】は辛労【しんろう】、子は楽、孫は乞食
• 「親苦労、子楽、孫ほいと」「親苦労、子楽、孫潰」「親苦労、子楽、孫貧乏」 etc.
• 親‌草鞋【わらじ】、倅【せがれ】草履【ぞうり】で、孫‌雪駄【せった】、曾孫【ひまご】の代には裸足【はだし】なりけり
  "parents (wear) sandals, kids shoes, grandchildren boots, great-grandchildren would become bare feet"

But more famous sayings with similar moral are:

• 児孫【じそん】のために美田【びでん】を買わず
• 売り家と唐様【からよう】で書く三代目【さんだいめ】