The passing of patio doors

Was rearranging my burgeoning collection of dark, fuzzy and largely unused photographs last night when I stumbled over my first ever digiscoping attempt. Despite complete mastery of the Coolpix 775, scope and patio door combination the result was a little disappointing. Of course, seven years, fours cameras and two patio doors later it is all so very different (e.g. see here). Where did all those patio doors go?