AFAIK Keysight MegaZoom uses ASICs with on-chip sample memory, so that's why it's relatively limited. You can get oscilloscopes with more conventional architect

AFAIK Keysight MegaZoom uses ASICs with on-chip sample memory, so that's why it's relatively limited. You can get oscilloscopes with more conventional architecture with FPGA connected to boatloads of external DRAM, but it comes with other tradeoffs. (usually much lower wfm/s)