You can still write by just doing "mount -o remount, rw /" beforehand.
The best way to fix this is to put the actual OS on an external disk. You absolutely must bootstrap from an SD card, there's no way around that. But that can be entirely read-only and then you bounce to the external drive. Or maybe you could do something like a PXE boot instead - copy a system image down from a server and boot that. Personal opinion, this is the only way I would try using Pis on a long-term basis.
The Jetson TK-1 board from NVIDIA includes a real SATA connector. Because it's GPGPU-capable it's also vastly more powerful than even a Pi2. It also has USB 3.0 so running swap on a memory stick would be much more performant.
I'm still sort of aggrieved that Solid State via DDR got caught up in lawsuits and is still commanding exploitative pricing. SATA for Solid State isn't exactly optimal either, though obviously not nearly as terrible as USB - SATA - SSD. SSDs with PCIe interfaces are so common now, it's shame not to see wider support for it.
A little tidbit I saw in HP's "The Machine" promotional talks was the idea of "fabric attached memory". If ARM 64 & RapidI/O ever make it into widespread use, it would be great if there were various forms of memory with RapidI/O interfaces commonly available.