About alloy junction transistors...
Alloy junction transistors were never scaled to industrial production, as the process for creating these types of transistors did not allow for such upscaling. However, this does mean they are fully capable in being hand made in a DIY process, unlike the more complicated, but more industrially suited, planar junctions.
These transistors if made successfully in a large enough quantity can make the idea of making an 8-bit computer from scratch with only a few people possible! This could be made as, as demostrated by the great engineers at gigatron.io and their 'Gigatron' computer, a 8-bit computer based purely on transistor-transistor logic (TLL) is possible, removing the largest bottleneck to small scale 8 bit computer production, complicated integrated circuits.
Although Sam Zeloof has shown that integrated circuits at a DIY scale can be made, it can be seen as he demonstates, that such production still requires the use of many highly-specialised equipment and technologies, such as a electron microscope. Which would not be possible from a 'from scratch' sense by a small group of people.