Allow me to elaborate… they had an engine change already. Granted it was a bit of a lateral shift. They’re 6+ years into development of a title which everyone, including Roberts, calls “extremely ambitious”. What’s also killing them (besides a massive feature backlog) is scope creep.
So you basically have a perfectionist trying to complete something extremely ambitious with new ideas that keep getting piled on and older cool ideas not being introduced quickly enough with looming pressure to release a title into a genre that’s extremely limited, while trying not to fall too far behind from a technology perspective and ensuring that the “final” product is not crap. All this is happening and people are still throwing buckets of money at the project.
Very few titles have been commercially successful after being in development for longer than 4 years. The viability drops off sharply after the 5th year and chances of success is virtually 0% if you go past the 10 year mark.
Some notable examples of ambitious games :
APB - Development started in 2005, was ultimately released late in 2010. It was an ambitious project attempted by industry veterans. They overshot their budget, failed to do any of their promised console releases and ultimately bankrupted the studio.
Daikatana - Development started around 1997. Ultimately released in 2000. Backed and developed by John Romero, industry veteran with massive hits like Wolfenstein, Doom and Quake under his belt at this stage. It was such a big failure it actually forced Ion Storm’s Dallas office to close.
Duke Nukem Forever - Development started around 1997, released in 2011. Several engine changes, studio changes, multiple rewrites.
etc etc etc