Because it's a sprint. You've got a finish line and you're racing towards it. Businesses don't function without prediction, and refactoring gets cut before roadmapped features. If feature development is a bottleneck in company growth, debt will grow, quickly.
Agreed. I regularly ask "Why are we running a marathon in a thousand sprints?".
Besides tech debt, a concern I have that I don't see brought up is burn out. With Scrum, every action you perform is micromanaged and with a push for "high velocity". There is no proverbial breathing room in this where the pressure lets up. At least with waterfall (for how we did it before Scrum), the windows of high pressure times were shorter. During the beginning of our 6 month waterfall, in parallel to spec work we'd be taking care of tech debt or implementing our pet feature and it was a time of mental recovery.
imho a problem with the implementation of SCRUM, but not necessarily restricted to SCRUM.
In a perfect SCRUM world you could not be forced to implement this in a time not of your own estimate. A feature that is so big that it takes more than a few days to implement has to be split...but well we all know how this plays our in reality most of the times...
Well there's your problem. How is that inherent to scrum?