Earlier quoted context omitted.
While I agree with the sentiment of #1, I would argue that sales are more important than marketing at this stage. You can spin your wheels “learning SEO” and “creating content” with very little tangible results. In the beginning, sales + product are just about all that matter.
Sales without marketing isn't the best strategy, it literally turns you into a one man[selling machine where everything is based on your time. Marketing develops channels of customers.
It also depends on who you're selling to as well. Consumer/SMB customers may require less sales efforts than enterprise customers. You will always want to start with talking to users regardless, which is sales.