There is a strange contradiction in the everyday photographic practice. Most pictures are taken in bright scenery with apertures between f/4 and f/11. Yet, the high speed lens is much valued and so is the ability of the photographer to take pictures in low ambient light. There is even a cult among Leica users to look at flash with disdain. A true Leica picture is made without flash, is an often heard statement.
In the past, slow speed films and medium aperture lenses were the norm. When photographers extended their domain for ‘fishing images’ to the twilight zone and the scarcely lit interiors of cafés and other public places, the requirement for fast emulsions and wide aperture lenses was a fact of life. Most high speed emulsions, then around ISO 400, were grainy and had in general a long tooth, which reduces the capability for under exposure and always generates a low contrast in the deep shadows.
In those days the standard f/2 workhorse was at the limit of useful work with a 400ISO film and German optical manufacturers were keen to extend this to f1.5 and even f/1.4. The Japanese topped this with f/1.2 and f/1.1 lenses. These lenses were generally of low contrast and did not match smoothly with the low contrast films. But the photographer could get the picture. It became a measure of craftsmanship to be able to take pictures with high speed lenses and relatively slow emulsions in low light situations. Then something curious happened. The different lens departments made the performance of the high speed lens the measure of its design competence. Leitz and later Leica, in particular, made the performance at the wide open aperture their yardstick of optical competence. The smooth and low contrast image of the older generations of lenses, coupled with a shallow depth of field made these lenses (at least for the taste of the generation at that time) destined for portraits. The cult of selective focus was born and with it the idea that this style was the best for general photography. The manufacturers, Leica in particular, were promoting these characteristics of their lenses with a great deal of verve.
The well known characteristics: high cost, shallow depth of field, large volume and careful focusing are negative side effects.
A moderate aperture lens with an opening of f/2.8 is nowadays not done, but it is the best compromise between cost, performance and size. Especially today when high sensor speeds with the equivalent of ISO 12500 are the norm. There is much to argue in favour of a moderate aperture lens of f/2.8. Optical performance can be outstanding (see the last Elmarit-M 2.8/90mm, the lenses are compact (see the collapsible Elmar-M 2/8/50 MM), there is no need for aspherical elements which reduces the manufacturing costs (compare the Summicron-M 2/75 ASPH with the Summarit-M 2.4/75 mm). The size can be reduced also, which is always a benefit.
The aperture of f/2.8 is fully adequate for even the current slow high resolution films when going the Kodak path.
It is good when the prestige element would be diminished for the high speed lenses. Most photographers would be delighted to have high performance, moderately-sized lenses to shoot their pictures in bright sunlight. You lug much volume and accept a high price tag for the occasional shot in the dusk. And flash is always an option. Skillful use of flash is also a mark of craftsmanship!

By the way: Adox HR50 and FX39 are now a beautiful combination with the reduced development times and reduced speed. The lens is the Apo_Summicron-M 2/50 mm ASPH, mostly used at f/2.8 or f/4