Yeah but supernovae are the product of stars with short lifespans (a few million to a billion years). Even after their fleeting outer layers are gone, they leave behind an ultra-dense core: either a neutron star, or in the case of the largest stars, a black hole. These cores are incredibly resistant to evaporation and even decay, and can last for countless eons: the 'shortest' lifespan I could find is 10^67 (10,000,000,000,000,000,000,000,000,000,000,000,00 0,000,000,000,000,000,000,000,000,000,000) years for small black holes.
So, even though TPM is past its prime, that's okay. It still has 99.9...% of its life left ahead of it!