Why is national debt a problem? Why do people even think it will actually be resolved?

The national debt can grow to however much it has to, while the whole economy is growing as well, and when the faction gets dissolved, several hundreds of years later or on whatever timeline, the debt gets dissolved with it.. ?

The government can just keep issuing out bonds, and not need to really pay it back, as in keep delaying it, by paying back a bond after it matures, and issuing another one right after, and keep on this cycle, till one day the issuer, that is the faction or it's federal bank, dissolves, taking the debt away with it.

Almost sort of like, if a person borrows $100 from a bank A, and after time comes to pay it back, they borrow 200$ from bank B to pay back the bank A, and this cycle continues, till there is no bank to lend more money from, to pay back the debt, or the person themself, dies, and takes away the debt with them.

Not saying that, if this were the case, it wouldn't leave the economy in utter collapse, and possibly irrecoverable for the coming hundreds or years. It would.

But there could be another possibility, a darker one, where robotics and AI takes over in such a degree that, the issuers of the bond, no longer have a need to be answerable to the lender.

So then the main question being, why is the national debt a problem, and why do people think that the debt will actually be resolved, as such what I stated above, won't happen*.*