Marketing is hard
I am an engineer. I am used to giving an input, waiting a second or so for the _system_ to do its magic, and then seeing an output.
Marketing is structurally similar. There is an input, there is a waiting period, and then there is an output.
The differences are:
You seldom, if ever, control the means of input
In marketing, your input could be your ads, your blog posts, your submissions to Product Hunt or Hacker News, or your slick IoT widget but in each case, someone else controls how your input is received by the system. You are always at the mercy of the engineers at Google or Facebook or Reddit or Product Hunt or Raspberry Pi to let you express your ideas just right™.
The only place where you have some semblance of control is on your own website or product. You can present your thoughts and ideas in a way most indicative of how you think. If you are not able to express yourself just right™, you can always hire talent to fix the problem.
You never have control over the waiting period
If you thought correctly managing the input was tough, you don't want to know how rough managing the wait period. The wait period is the time between submitting your input and seeing a response. This wait period can range from 0 seconds to infinity.
How marketers work with so much uncertainty is unfathomable to me. Think back to the heartburn that came with submitting your resume and then never hearing back from the hiring manager. A marketer exposes themselves to this treatment every single day of their job.
You never have control over people's responses
People are complicated. To paraphrase Mike Tyson, everyone has the best marketing plans until some troll comes along and punches you in the face. And I use troll not as a pejorative. As often as not, the people I am calling trolls are well meaning, fair minded conscientious objectors to whatever you are proposing.
Yet, in your head, all you can think is that this person is being difficult for the sake of being difficult. "If only this jackass would see things the way I do!" you think to yourself but obviously, that nearly never happens.
Conclusion
If you are an engineer who is also handling your startup's marketing responsibilities, take heart. The uphill-both-ways seeming struggle to gain traction is just par for the course. Good luck with the fight. I'm right here with you, pushing uphill.