I'd split the difference and say the cons that low quality software creates only matter
sometimes.
E.g. Concur is primarily feature-complete and will only ever need to evolve gradually.
So the drawbacks of being brittle, kludged-together, and incapable of making rapid feature changes doesn't really matter.
In some other products, that matters a huge deal.
So the tl;dr is, as always, optimize for the things that actually matter for your particular situation.
