The problem is the business models revolve around the software. You cannot directly compare them without also comparing the complexity and manpower required to achieve it. Just take a look at W3C spec and you’ll see just how many cases there are to handle when making a browser. Not to mention making it secure and performant. Also, if you want to support web push technology on your browser you also need to have infrastructure to maintain. A donation may work but you’ll have to be content with slow development since the resources can be uncertain.