Shadow, the argument you're making against "user" full-nodes is not an argument I ever made. Not once did I ever mention "user" full-nodes or making the case for the ability of users to run full-nodes on Raspberry Pis.
There is a big difference between "user" full-nodes and just the idea of full-nodes in general. Essentially if you're a non-mining Bitcoin business, you're going to want to run a full node. As a business, you're not going to want to trust your business to some other third-party that is running a full-node. Secondly, Coinbase, for example, as an Exchange will want to run a full-node to ensure that their transactions are fully validated and that they're also a complete check and balance against the rest of the community. If the only full-nodes out there were miners, then that would mean miners would be able to dictate the business decisions that Coinbase as an exchange were to make. Also, since Coinbase is a business that relies directly on its userbase, Coinbase has a vested interest in listening to that user base to determine what path to follow. This is the key market mechanism that people miss when they place too much emphasis on the power that miners have over Bitcoin. Coinbase isn't in the mining business, but it most assuredly is in the business of making sure that Bitcoin follows the path that the market demands. That is essentially its entire business model and that model depends directly on running a non-mining full-node.
The article you linked to and the argument you've made only make sense when talking about "user" full-nodes, but don't make much sense in the context of what I stated above.
Finally, if you value decentralization (which the article never mentions), then you must also value non-mining full-nodes. I run cold-storage watch only Electrum SPV wallet. At any given time it is connected to about 10 different servers, many of them are Tor hidden servers, and are very geographically diverse. This is a very critical component when it comes to creating a payment network that is censorship resistant. Bitcoin mining is essentially performing energy market arbitrage by being able to be located in areas with cheap electricity. Because of this, there is a reason why a large chunk of the mining resources are located in China. I mine with an ASIC at my house and use the Slushpool mining pool since it gives me a vote as to which Bitcoin version I mine for. Since most mining takes place in pools, if only miners were the ones running full-nodes, then my SPV wallet would not be making nearly as many diverse connections around the globe. This is very bad for decentralization and censorship resistance. Large numbers of geographically diverse full-nodes provides a proper check against mining, especially when that mining is not nearly as geographically diverse.
I agree that Bitcoin without mining is not Bitcoin, but if you put too much emphasis on the power that mining has over the network, then I'd absolutely argue that Bitcoin without a large number of geographically diverse full-nodes is not Bitcoin either.