I suspect that it is probably much more complex than that
Yes, it's somewhat more complex that Freddy thought. To start with his impression
that markets would sell almost everything and were central to town/village life.
The last part of that sentence contradicts one of the clearest points in the literature: "substantial villages ... sometimes had populations similar to those of small towns, but are distinguished by their lack of a market, which in contemporary gazetteers and directories was often the crucial defining feature of urban status."† So contemporaries recognized that the presence of a market was an important feature of economic life.
But what exactly is a "market"? The OED gives the oldest meaning of "market" as "a place at which trade is conducted", but then elaborates that as "a meeting or gathering together of people for the purchase and sale of provisions or livestock, publicly displayed, at a fixed time and place; the occasion or time of this." So it elides "market" with market
place; it is very difficult to disentangle the two meanings. The in-game Market (I will use a capital M for it) is surely using the word in the sense of 'place'. So how often does a 'market' (in the sense of a meeting) take place there? Many markets were weekly affairs and since pak128.Britain-Ex only has a daily cycle, the in-game Market surely represents both daily and weekly markets.
That helps to answer the question that James raises:
why were goods being sold in stalls in squares or in the street rather than in dedicated buildings?
Stalls, rather than buildings, were used because a weekly market did not justify investing in a permanent building. And even in the context of a daily market, it would not necessarily be the same traders at the same place every day. A trader might be at one town on Monday and another on Tuesday. Or she might only be present at the marketplace for part of each day, since she also had to spend time on the farm.
And I'm not sure how big the distinction between stalls and buildings would have been in this era. James clearly distinguished our Market from permanent, indoor market halls. I guess this is based on the graphics but it does rub uneasily against the fact that the economic purposes of the two seem to have been very similar; market halls were often the enclosure of an existing market. The pak's Market might also be said to represent the annual or quarterly markets or fairs that were of regional importance.
I recommend this website:
https://www.british-history.ac.uk/vch/oxon/vol4/pp305-312
Yes, Oxford provides good examples of many of these issues. There is a very successful
Covered Market there today (I highly recommend the English breakfast at Brown's Cafe!), which is open daily (except Sundays). But it grew out of the existing non-daily markets. The article also includes fairs (including St Giles' Fair, which is also alive and well), which strengthens the case that this should be included in our understanding of the in-game market.
Another definitional issue is whether we mean retail or wholesale markets. James' paradigmatic example was the Covent Garden fruit and flower market, which was primarily a wholesale market. And this is typical for the period: markets were used by urban consumers but they were also (perhaps even primarily) aimed at the pedlars and village shopkeepers who supplied the (rural) majority of the population. But the in-game Market is visited by consumers from residential populations and it does not supply other industries.
There are plenty of records of specific types of market
This is true. In one sense, there is an overwhelmingly large number of records, because searching for "market" gets you innumerable references to the abstract sense (as in "the labour market").
But unfortunately there do not seem to be many records
from specific markets. One of the best sources of information about 18th and 19th century shops were trade directories, but they do not generally include market traders. Another is the shop tax, which seems not to have applied to markets either. I also suspect that market traders kept relatively few written records. And the goods we are interested in (bread and textiles) did not attract duties, so we do not have the relatively good documentation that exists for beer and spirits, etc. Our best sources are likely to be probate records and....
Perhaps there might be some fiction literature (Dickens, maybe?) that mentions these things at a market at that time?
I thought of this too and one of the research articles cited Eliot's
The Mill on the Floss. I trawled though it and got some useful background info on bazaars, but nothing definitive for our purpose.
† Stobart, Jon and Bailey, Lucy (2017) 'Retail revolution and the village shop, c. 1660–1860' in Economic History Review 71(2), 393-417. References from preprint at
https://pure.northampton.ac.uk/files/8621390/Stobart_Jon_Bailey_Lucy_WOL_2017_Retail_revolution_and_the_village_shop_c_1660_1860.pdf 18/AUG/2020.