Far and away the best prize that life offers is the chance to work hard at work worth doing. – Theodore Roosevelt

In the Entrepreneurial Context:
Who loves work, right ? Very few employees will answer positively, but many entrepreneurs or business owners will answer positively!

Most entrepreneurs and business owners launch their business because they like what they want to do. Of course there are a lot that do it for the money, but a big majority invest their time and money because they believe in their dream. Thus it is a pleasure for most entrepreneur running their business.

Far and away the best prize that life offers is the chance to work hard at work worth doing.

– Theodore Roosevelt

In the Global Context / Startups:
The second part, work worth doing, Startups are often changing things for the better, advancing civilization in many ways, thus this quote do apply to tech startups. I am sure people working at SpaceX, Tesla, Facebook, Google and so on do feel this life satisfaction.

Generalization:
When you like what you do, you work hard, and you are happy about it. If the thing you do would have a positive outcome that benefits your family, nation, the planet, humanity, then this work worth doing would bring you pride. Your prize is working for something that matters, in contrast with all the other mundane jobs that are really just to provide food on the table.