No Congress can bind a future Congress.
Entitlements (non-discretionary spending) sure look like a previous Congress has bound the current Congress...
Theoretically true, but there are factors that make it difficult to change existing laws that govern long-term commitments and constraints. The Budget Control Act of 2011 is one of those things. If you have a president who will not sign a bill undoing past law, Congress is pretty much stuck with what's on the books, until circumstances change, like now with the 2011 law.