Unpaid debt exists until it is discharged.
Expiration of credit report exclusion periods for derogs reported on the debt simply prevents those derogs from continuing to appear in your CR, and thus become known to others based only on a pull of your credit report.
Expiration of SOL governs their ability to sue and obtain a court judgment that you pay the debt.
Neither of those (except for two states where expiration of SOL also discharges the debt) affect the continued obligation to pay the debt.
Discharge of a debt occurs if the debt is paid or is cancelled by the creditor, or some provision of law discharges the debt, such as a BK.
If you dont pay the debt, prospective creditors may still be able to become aware of its presence by means other than simply pulling your CR and not seeing derogs posted under the account with no reporting that the debt is paid. They can simply ask in a credit app for your disclosure of any unpaid debt, or can see a prior OC reporting of a prior debt with no subsequent reporting of paid. Aditionally, if the derog is based on a public record, such as a judgment, a simple public records search will provide them that information without having to obtain it from your credit report.
You take your chances when relying only on credit report exclusion of reported derogs to shield the presence of contunued unpaid debt.
If you are applying for relatively low amounts of credit, the creditor may not do a more comperhensive manual review, and thus may not become aware of its presence.
However, as the amount of credit sought increases, the creditor is more likely to do a more comprehensive manual review, and may still become aware of the unpaid debt. It is then up to them as to whether the presence of unpaid debt is a factor in their decision making. Many mortgage lendors, for example, will require the payment of any delinquent debt as a condition for any mortgage approval.
Additionally, a debt collector can continue to pull your CR after CR exclusion of their collection or after expiration of SOL, so you could continue to accrue new inquiries.
It is always best, other than $ out of pocket, to clear one's history of any unpaid, delinquent debt.
