Well yes, but then the NES, SNES, PS1 and PS2 competed quite well against their respective next-gen consoles. True following history would suggest that the Wii should be the one to compete against the newbies, but this gen has been a bit odd and the combined force of PS3 & 360 has become the end of gen sales power.
I would guess that PS3 + 360 will be able to compete against the WiiU and win for most of the first year, then their drop off will depend on what MS and Sony plan, I am doubtful both will wait more than 1 year after WiiU to release, in fact I am doubtful even 1 of the pair will wait much more than a year. The WiiU's success will depend more on itself than the PS360 downfall though, if it is to be a success then it will likely be thrashing PS3+360 combined sales by or just after Christmas 2013.
Also twin implies two... you can't have a third twin.
