RTGs are fun and fine for many fringe purposes. At the milliwatts-to-watts scale, the amount of radioisotopes makes them way too risky to use in commodity electronics. Fine for fringe, remote power, but not great for like laptops.

For reference, the amount of Strontium-90 in one 250 Watt thermal (~10 Watt electric) RTG could give out about 63 million certain death 10 Sievert doses if people were to ingest or inhale all of it.

Good thing all the University funding is being cut. Otherwise the US would continue to lead in useful R&D. Who would want that...;-p