140 may be rejected because the income of employer

could not prove affordability. I haven't seen anyone being rejected because they waited 2 years to file 140 after their LC being approved.
X's LC was approved in 2003 (filed in 2001), ted his I140/485 applications in Feb 2006. He got his green card on 12/5/2006.

Disclaimer: FYI only, not a legal advice.