This morning, when I was driving my kids to school, I was behind a truck that said “Father & Son Contractors: Specializing in Full Service Apartment Turnovers” Really interesting. These guys might have just focused on cleaning, or painting, or replacement of broken appliances, but no. They understand that there’s a customer out there who needs all the services at once, and usually under a deadline. They have realized that they can probably make more money and enjoy higher customer satisfaction if they focus on the customer's need instead of their own functional expertise.
In nearly every business model, there is a tension between offering what the vendor likes to do and offering what the customer needs.
If the customer has to find all the different experts to solve his problem, he has a big hassle. He might enjoy a little discount and definitely will have flexibility about whom to use, but it's likely that he doesn't have the skillset or relationships (unless in this case, if he's an apartment building manager).
If the vendor coordinates it all, that creates some work up front for the vendor, to find all the functional experts, but over time, they can amortise that effort over many customers. It mght be a hassle, but longterm, they'll get paid more AND probably get more customers because they focused on the customer's problem.
What problem do you solve for your customers? Do you solve it completely, or do you expect them to put together their own team to complement your strengths? and whether you have the subs do do that effectively. Totally different then the path of being the big brain, but I think it’s much easier to scale.