The IRS does not have unlimited time to collect an unpaid balance. Under §6502(a)(1), the tax (and any related penalties and interest) may be collected by levy or a court proceeding, but only if the levy is made or the proceeding begins within ten years after the assessment of the tax.
https://www.tomtalkstaxes.com/p/an-overview-of-the-collection-statute (May 12, 2025)