Astroron, the two big NEO surveys LINEAR and NEAT werent up and running at full tilt boogie till after those two last most recent "bright comets" you mentioned were discovered - i think LINEAR was 1997 and NEAT in late 1995/early '96? - they have been getting better at it all the time too! scary
There are still areas of the sky that these two big northern surveys dont cover - southern hemisphere for one thing
also they didnt/ still dont? search completely down low on the horizon, near the sun, at the pole(s) or fully in the milky way even now
Although the Sidings Spring Survey is well on its way now, - and there are a few amateur surveys that are successful also, - Vello Tabur comes to mind of course
- they still dont cover the entire southern sky yet? (i think? the northern hemisphere sky is at 80% coverage now!!!!!) also weather is involved as well as other factors I too.
I dont know about calling their equipment exactly modest - in Yuji Hyakutake's case, a pair of fujinon 150mm bino's !! how much are they? although it is still affordable I guess if your keen enough - about the same as a small new car?
Cheers
Kearn
ps I am not an expert!! I only have a very basic knowledge of the search for comets/NEO's - theres a lot more to it than what i mentioned of course
pps thnx for compliment re our pictures too mate