Not having a millionaire does not mean that the country earns less wealth. Millionaires more often have created or inhererited a position where they can profit from the efforts of others.
for example, if he is a company owner or shareholder, it is someone else that is doing the work and creating the wealth. Someone else can own the shares or the company with no impact to the community.
If he is Geoffrey Archer or Lord Black, then having him out of circulation will do nothing but good.
If he is a footballer or other entertainer, his loss will not reduce national wealth.
If he is a drug-dealer, loan-shark or slum landlord, his death will not reduce national wealth.
On the other hand if he is an inventor or trader, there might be a pause until the gap is filled.