This is why you need a ZX Microdrive...
Have they improved tape's loading speed from the 8-bit days?
If the ZX Spectrum could look approximately 16 KB in a minute (*), that's around 960 KB an hour, 23 MB in a day, 713 MB in a month (around a CD-R's worth) and 8.395 GB per year (around a dual-layer DVD's worth).
Or put another way, a gigabyte would take 44.5 days to load, a terabyte a thousand times longer at 44,500 days (i.e. 122 years), a petabyte 122,000 years, an exabyte 122 million years (which is probably in the ballpark of the uncompressed maximum capacity of IBM's 2.7 exabyte robot library).
And I bet that 121,999,999 years, 364 days, 23 hours and 58 minutes into the loading time it would say "R Tape Loading Error, 0:1"