Hi Paul... I can not address the question of Forsythe's book.
I do believe that the intention of the Truitt's book was to document some of the better examples of the regions work. Historically, their first publications appeared not too long after the fall of the iron curtain, a political entity that had greatly restricted the west's access to the type of information they started to accumulate.
The production of Czech (Bohemian) glass is all across the board as far as quality levels go. There are even large disparities in quality levels within companies depending on the time period one examines. In looking at Kralik as an example, the company(s) are actually the result of divisions and inheritance over a period of around 25 years. (see Loetz.com under Kralik for a brief historical summary) The original division occurred in 1877 after Wilhelm Kralik died. One portion of the company retained the name of Meyr’s Neffe. This portion of the company is know to have produced very high quality production. The other portion of the company was taken over by two other sons and took on the name of "Wilhelm Kralik Sohn". This division of the original company is the Kralik work we see and recognize the most. The quality of their work varied greatly over the next 40 years, and they are known to have produced not only some very generic and mundane work, but to have also produced some very advance and creative deco era work.
I have examples of early Bohemian glass, some of which you would swear were designed yesterday. I have also seen examples that even if they were free, I would not want in my collection......
There are, as you see and examine examples of works that are stamped "Made In Czechoslovakia", or identified as Bohemian, great disparities in the quality.... There are obviously differences in the imagination and talent of designers at different factories, and as with all markets, there are those that take pride in their work, and those that simply do it for the money..... Time may change many things, but that does not appear to be one of them.....
Hope this helps, Craig