Simple Answer...NO! Reason's Being :-
1. Cash
WWE are making considerable more money than they ever were doing during the turn of the century & towards the end of the attitude era. Why would they compromise that & risk losing a whole ton of money, especially while ratings are down! If anything the WWE would be more likely to start a 4th Brand than sending it back to 1!
2. Schedule
The Superstars allready have a tough enough schedule as it is, think about if your the top guy. It's hard enough to keep up with just the Raw Live events let alone a pile of Smackdown House shows added onto that. WWE's run of inuries this year has been contributed by VERY Busy schedules with House Show's & TV Tapings & so on... Think of the injuries that would occur if the schedule was doubled... Yer, exactly!
3. Opportunites
Although the programming would be far more entertaining no doubt, the opportunity for younger guys to step up & make it to the Main Event would be very limited indeed! How would you expect such people as CM Punk, Matt Hardy, Chuck Palumbo, Carlito & others be used on the show! Answer = they wouldn't because it would be too star studded for guys struggling to make it on TV anyweis! Just because there are more guys on a show deosn't mean it's going to be a ton better. Look at Raw This summer, they nick everbody from SmackDown!, Clogg up the Main Event... & have the same stale Ratings, & the programming quality itself hasn't improved a bit. The staleness of the show's isn't down to not enough people, it's the booking itself!
The brands as a whole is working fine ATM... There are plenty of opportunities for younger guys to step up into the Main Event on both SmackDown & ECW! (Not so much on Raw) Why would WWE compromise this & just combine the Brands. It's just stupid. One day you'll find out from a BUSINESS standpoint, that the Brand Extension is here to stay & is far better than just 1 roster. I have a feeeling your just wanting WWE to collect that Attitude era feeling again... But the truth is, even if they were to combine the Roster's The Show would still be shitty & would pale in comaprison to 1997-2003... Wrestling's moved on, we can't live in the Attitude Era for ever, people need to realise this that no amtter how hard you wish... Those days are the past & there's no going back.
& Smacky-Backy isn't a poor Show, yes it may be a little worse than back this time last year but it's always in transition, as you can see new guys coming quite often! Plus, SmackDown usualy has the better matches out of all three shows, so TBH it can't be THAT bad!