1) Maybe? Did they have the resources to pay someone? And, as you pointed out, you got sucked into support for a role you didn't get paid. This increased their dependency on you and pulls you out of your normal economic/professional role. Probably not unethical, but certainly led to undesirable results (for you, great for them).
2) Your free consultancy extends his runway, which means he has a greater chance of success and puts him in a better position to contribute by hiring and spending in the future.
3) You also keep the retail chain in existence, and have spent your money more wisely rather than overpaying (by labor rates at least) for someone else to do what was actually a quick and easy job.
Honestly, though. You seem to be thinking that I'm opposed to giving. All I said is that it's complicated when you start giving to (and sometimes, in essence, taking from) others. Look at that Africa t-shirt versus textile manufacture example in another thread. Millions of people clothed, thousands of people out of (otherwise sustainable) work. The calculus is non-trivial. Clothing people is a good thing. Putting thousands of people out of work is probably a bad thing (depends on what the work is, and what they can do after it). Which one outweighs the other. In the long term, eliminating an industry from a region is probably going to turn out to be a worse thing as it eliminates the ability of those individuals participating in it to feed and clothe themselves and contribute financially to their local economy. Compared to other forms of giving (versus free t-shirts) that would have enabled people to build up more businesses and industries where they would then be able to afford and/or manufacture more clothing (or whatever other needed goods) locally/regionally. Or purchase them from abroad by producing some goods/services they could sell globally.