The cost to a company of an $80k/yr employee is well more than $40/hr.

You need to account for time not working, such as paid holidays, vacation and sick time. Also, you need to factor the amount the company pays in addition to the salary such as payroll tax, benefits, cost of the space, tools and amenities to let the employee do their job. These are all costs that will be absorbed by the freelancer.

All said and done, a company pays probably $60/hr, minimum, to hire an employee at $80k per year.

Doubling or tripling your salaried employment rate is not uncommon when freelancing in order to maintain the SAME level of income to account for non-billed time. This can be adjusted for longer term contracts.

My point is $150/hr is not too hard to justify as a consulting rate for an equivalent employee making in the salary range you specify.

The other consideration is the role you're in with the company who hires you. Are they hiring you to interface with an existing tech team, or is it a solo gig, where you also will be playing business analyst and project manager. The latter, IMO, would also justify a higher rate, assuming one is competent at it and is providing that additional value.

Charge your next client $100/hour then. What is the worst thing that could happen? They say no? Honestly if they say no you probably need to focus more on your pitch. Learn to sell and hourly rates are not your concern. I would learn to sell and then learn to sell your expertise in a different format than hourly.

Btw I have the same skill set as you but I sell myself as a consultant that just happens to code. A good client wants to see you as an asset that can solve problems not a coder that presumably needs to be managed.

Consider the fact that if the average pay is $70-$80k and you're working for a company that does client work, the company is charging its clients a lot more than $35-$40/hour for access to you.