Yes, it is common for some bugs to never be fixed because it's always considered to be more worthwhile for the business to either fix different ones, perform tasks or (most commonly) implement new features to achieve new business objectives and increase revenue. I experience this myself particularly with old browser bugs that I have to keep testing and seeing and knowing that other devs don't have to see them as they are not exactly testing IE8.
Some options are
- Keep them in the backlog and revisit them each week. This way you spread the pain and increase the likelihood of attention.
- Make a schedule to fix, say, 1 per month, so they only take a small % of time in comparison to new feature work.
- Fix them on technical fix fridays.
- Have an occasional 'bug fix week' just for fixing old bugs even small ones.
- Put them in the icebox and consider looking at them periodically or occasionally. or never.
- Delete them and rely on the product owner or the team to remember the little stuff.
- Focus on educating the team more on good practices and approaches and why to do them and what the aniti-patterns are. Then tickets that are relevant will then have had the general case made for them up front.