That income is not coming from mining Ethereum and, as time goes on, the amount of any coin you can mine diminishes (sometimes rapidly).

The only way to avoid diminishing mining returns as difficulty increases is to swap to a new, lesser known coin. Eventually you run out of coins to swap to or the ones you are mining don't go up in value (because if they did, bigger miners would come in and knock you out of the game as the difficulty shoots up). All the time your GPUs are ageing too.

If you want a steady income with arguably a lesser risk profile and more staying power than personal mining offers, why not put some money in to coins that offer node payouts?