Because 99.9% of people will never self host. They would much rather just buy a product that is not setup as a scam. The scam part is less important to most people than the lack of effort required.
This isn't a thing to get into for the money. It would be about the FOSS aspect. Doing something like this would not break even for the time and labor involved. It might be worth doing for positive digital neighbors, but I am not at all interested in doing anything for negative or rude people.
I come from a background of being a buyer for a chain of bike shops where I spent millions of dollars based upon knowledge of how such markets work. The entry level customer is all that really matters. The extra stuff is just to woo them into the store.
In a place like this, if you engage, you're actually irrelevant. If you want to target growth, get a lurker to engage for the first time. Getting some random lurkers to buy into the hardware to self host because they care about software freedom is far far more effective than the current ecosystem. When servers are not updated, and people shut down because of administration, it says this is not viable for the average person with a life. So make this easy for the individual. It is such an obvious thing to do.
The present system is basically like go compile OpenWRT for your router and people whining about how it is not fucking hard. It is not, but most people just do nor care to try it. They just want to buy a device, plug it in, and be done. Half of these devices are on factory original passwords. This is the real scope of what people are capable of and expect. The mismatch is easily solved by packing the fediverse as a device. The alternates are great for the 0.1%. I am not talking about you all. I am talking about something that could go from 0.1% to 5% of the fediverse is self hosted, and likely much larger. The whole endeavor would be like a coop socialist kind of thing from the ground up.