The high end Intel Macs supported over a TB of RAM, over 5 years ago. It's kinda crazy Apple's own high end chips didn't support more RAM. Also, the LLM use case isn't new... Though DeepSeek itself may be. RAM requirements always go up.
The presence of unified memory does not necessarily make a system better. It’s a trade off: the M-series systems have high memory bandwidth thanks to the large number of memory channels, and the integrated GPUs are faster than most others. But you can’t swap in a faster GPU, and when using large LLMs even a Mac Studio is quite slow compared to using discrete GPUs.