It's more like you start a new pizza company and you're not allowed to use Stallman's Pizza Cookbook, which has some recipes you like. You can still hash out the recipes by yourself, with much annoying time and effort (and wasted food). Stallman's just not letting you benefit from his cookbook, because he thinks all pizza should be free.
If recipes, then the metaphor makes no sense. You can use the "recipe" that is LibreOffice to produce "pizza" that is work products that people would pay for (such as a lawyer drafting contracts, a consultant making spreadsheets, etc). Nothing in the GPL stops someone from profiting from the output of a GPL'd program.
If pizza, then I can only assume the "recipes" would be programs that produce programs, such as compilers or parser-generators. In that case the metaphor also falls apart, since GNU programs of that type have license exceptions that make the output of those programs (and the additional compilation files needed to run like libc and bison include files) usable without following the GPL.
No, you'd just have to share your recipes whenever you sold the pizza. You can still charge for the pizza (or not) if you want - and the guy who buys it from you can sell it or give it away or whatever.
The way you feel when you can't use GPL code in your startup
Is the same way I feel when I can't use Mickey Mouse or Mario for a toy in my toy company.