As somebody who is a skilled backend developer the value I provide is not as measurable. How can I justify charging a large weekly rate, when almost nobody can provide an objective number of the value I provide?
Learn to do something which is more measurable, or figure out ways to measure some particular aspect of value you can bring. In back-end software, it will most likely be around performance or security. Doing a security audit then proposing remediation... if the company has already been hacked, they (should) understand the value rather quickly. If not... it would be a harder sell.
Performance? Would be hard, I think, without being a brand and people seeking you out. Speeding up an ecommerce site can definitely have measurable impact on bottom line but... if a company is big enough where that would have meaningful impact, they probably already have a team of people to navigate through to convince them of your value/skill/ability.
I work with companies operating at a large scale. Downtime costs $xxx,000/minute.
Developers cost lots of money, improving their productivity by a little bit pays huge dividends.
If the company has big events like Black Friday or Superbowl commercials, keeping the site up during those events is worth paying for.
Many not so big companies spend 6 figures per month in AWS bills.
Lots of work for a backend consultant.
So I guess I would counter what you said with experience/network rather than a brand.
* do work for someone you know
* write a case study documenting success
* repeat with a slightly bigger customer
Margins matter too, not just headcount. Someone could do $2m/year but make less than someone doing $800k/year with better margins.
Doing perf/security reviews of a niche like that (woo, magento, etc) would probably still be a place to focus and make money, if you want to stay 'back end' (or at least technical). But even then, some of the measurable stuff will be needed - "we reduced the load times by 45% on the checkout page, and conversions went up 17%, adding $87k in profit last year".
99% don't care unless and until they get hacked, they will also forget about it all in 2 months.
If they don't get hacked for years they will just attribute that to luck and probability, not valuable security consulting.
And if they do... you can guess that one.
Lots of smaller businesses just don't care. They also don't have "chief somethings" to tell them it's important, or to do it to save their own asses just in case.
They just fly blind and in many cases they get lucky which further solidifies their beliefs.
And in the odd case when they get screwed they just bury it and move on.
Or post a "we are very sorry! security is our TOP PRIORITY!" message somewhere and move on.
I mean just look at the Equifax fiasco. Then scale that down to the smaller companies and see what you end up with...
if anything, knowing how much you can do (10 hrs of work) per week, makes it easier for you to propose how much value you can provide each week, no?