I once was an intern in a company that wanted to rewrite the whole Reddit code in .net. The founder was a charming person and managed to raise a huge pile of money. "We can redo this with current technology and elegant design! We will run circles around Reddit!". We had a great time. Free snacks, lot's of parties, luxurious office furniture, skateboarding in the hall... In the end, the company ran out of money before…
In two cases, the guys running it knew it was going to fail from day one and their business model was to do this in two year chunks, syphon the cash out of the VCs after talking the product up, live the high life and disappear for a bit.
I felt no shame working for them back then but I do now.