These illustrate the dangers of assuming economic systems are "closed", and that all possible assumptions will apply in perpetuity. Technological change can occur very rapidly, and old assumptions can be suddenly undermined by what appear to be minor changes.
The definitive misuse of linear extrapolation occurred during a survey of London traffic in Victorian England. It was seriously estimated that vehicular traffic would squelsh to a nasty halt by 1925 because the roads, by then, would be covered in horse manure to a depth of 12.652 feet.
Everyone knows of the gross miscalculations made in the early 1950s just as the first leaps in electronic computing were being made. It was confidently predicted that three or four EDSACs would more than cope with all the foreseeable scientific computing requirements of the UK. This type of error arises from the belief that inventions fulfill existing needs rather than create new ones. Henry Ford did not start by conducting surveys on the demand for personal transportation. Had he done so he might well have devoted his talents to improving the railroads or equipping the road sweepers with bigger shovels.
In the early 1950s the long-term prospects for paper-tape and its accessories appeared rosy, in spite of the rival claims of the punched card lobby. In fact, the card v. tape controversy raged for some years, mirroring the altercations between Fortran and Algol devotees. Those who saw salvation in "either/or" terms failed to recognize that both cards and tape would be condemned to near-extinction by data-entry and storage technologies not then dreamed of. Ah, the dangers of sales-forecasts.
The seers of 1987, poring over the tabulations of past trends, often extrapolate without recognizing the essential discontinuities of technological progress. To add insult to injury the predictions are often made with stunning precision: "Micro software sales will increase by 18.392%..." The layperson suitably impressed by this spurious quantification. Who can dispute a number with three decimal places?