I think keeping old inactive accounts have same implications as keeping an inoperative Bank account. Bank's do not allow operations in the account without a request from the customer. However the balance in the account remains protected if it is more than negligible (prescribed minimum). Negligible balances become zero after a period of time due to application of charges. The banks mark the accounts inoperative as per uniform laws and procedures. Similarly HubPage, I think, will first announce the policy guidelines and thereafter make such accounts inactive in two ways:
1) Where the balances ( articles as Hubs) are below the prescribed minimum.
2) Where the balances ( articles as Hubs) are more than the prescribed minimum.
In the first case HubPages may like to delete accounts to clear its database of the undesired burden. The user may have to make fresh ID after passing through quality control tests.
In the 2nd case HubPage may like to maintain the Hubs of the account holder and transfer the user details to Inactive accounts. Such accounts may be allowed to be revived after passing through security questions.
However if an user expires/dies then I think the HubPages has not made any visible policy so as to transfer the Hubs to the legal heirs or successor along with revenue accruing in the account. In the virtual world I have not come across any such policies where while making Profiles one may be prompted to fill in the email ID, Name, address or mobile number of the nominee so appointed.
If such policies are framed than, I think, there may be provision to send an email or SMS to the appointed successor's (Nominee's) for his/her confirmation. After receiving the confirmation the Profile of the Hubber may show "verified nominee or successor" to the estate of the owner at HubPages.Moreover during the life time the hubber's account if the account has the tendency to become inactive due to hubber being incapacitated due to illness or otherwise then, I think, HubPages may provide the Hubber's account to be transferred in the name of a person of his/her choice in similar fashion as Blogger allows transfer of Blogs from one author to another author with 100% ownership and withdraws his/her ownership.
In such situations the HP may take another PayPal email ID of choice of transferee and I think Google Adsense has the provision of transferring Google Adsense account to transferee after proper verification. These provision can solve future problems.