While this may come as good news to some, it may also be indicative that the future further widening of the 401 is a couple years off. MTO contract 2014-2006, which is for the reconstruction and widening of the Mavis Road overpass recently closed, with Graham Bros being the low bidder at just over 12 million dollars. The widening of this overpass serves as a precursor to the widening of the 401, much like the same works that occurred at Hurontario.
The thing is, the reconstruction of the Hurontario overpass and the widening of the 401 was parceled together as one contract (2009-2031).
The fact that the Mavis Road works aren't coupled together with the highway widening under one contract seems to be indicative that the MTO plans to proceed with the actual highway widening at a later date.
The MTO is proceeding with the widening of the 410 this year (Contract 2014-2026), this is probably another reason not to proceed with the 401 widening right away, as the widening of the 410 will be over a 100 million dollar contract and will definitely be eating up the MTO's budget.
Fun fact, when the Mavis Road interchange was built, it was future proofed for the eventual widening of the 401. The bridge actually rests on piers at each end instead of soil abutments. So when they widen it, they won't have to build any additional bridge pier supports, they will simply dig out each end, throw a bridge deck down which will then rest on soil abutments and the existing bridge piers.
Contract info can be found here:
https://www.raqs.merx.com/public/bulletin/contractView.jsf?id=24608501