Based on the names you mention, I'm going to assume that you are referring to the early modern "Scientific Revolution," as it's often called, and I'm going to limit my response to that period. Ancient and medieval science are another question altogether. Also, I'm not a specialist in the history of science, just medieval and early modern history.

Early modern scientists in what is now Eastern Europe weren't a different community from those in Western Europe. The astronomer Nicolaus Copernicus, for example, was Polish. He studied in both Krakow and in Italy. He read the books of "Western" writers and they read his. Latin was the common language for all scholars of the period, and the "Western" scientific community was essentially defined by the area in which that was the language of scholarship. In the northeast, this would end at the borders of the Eastern Orthodox church, and in the southeast, the (mostly Muslim) Ottoman Empire.

The picture is also a bit more complex than just Italy, France, and Britain dominating the scene. Italy was more important in the slightly earlier phase than the later, for example. French scientists were more dominant in the theoretical side of things, while English science tended more to pursue practical experimentation. Just as is the case today, science and technology are closely interrelated, and depended on the funding of patrons, so places that were more economically prosperous and had highly skilled craftsmen had an edge. Many of Europe's large commercial cities were in England, France, and Italy, because of a combination of factors like proximity to inexpensive water-borne transportation, deposits of natural resources, and quality and quantity of farmland.

One example of the intersection of commercial wealth, skilled craftsmen, and scientific progress is the career of Leeuwenhoek, a pioneer in microscopy. Leewenhoek was a cloth merchant in a wealthy commercial city, Delft. He became interested in lens-grinding because he wanted a better magnifying glass to determine the quality of his cloth. He was able to learn lens-grinding from the skilled craftsmen who were already making and selling the kinds of lenses Leeuwenhoek was using. He took the basic skills he learned from them and experimented further. It's easy for us to forget that most people didn't have the free time and spare cash to spend on this kind of thing. Through primarily trial and error, as far as we know, Leeuwenhoek discovered a process for making better lenses than any before and, being apparently a naturally curious fellow, looked at all sorts of things under them. He discovered the existence of single-cell organisms in this way. Other scientists were able to learn about and build upon his discovery because he had a friend who translated Leeuwenhoek's writings into Latin so they could be distributed by the Royal Society, an English scientific association.

TLDR: Scientists in the Latin-speaking world all participated in the same Early Modern scientific community, no matter where they were geographically. There were not so many of them in places that were relatively less prosperous and urban, as was the case in most of what is now Eastern Europe.

I can't answer your question directly, but it's worth pointing out that it's somewhat inaccurate to associate the rise of modern science with Western Europe specifically.

• Copernicus was educated in Italy but worked in Poland.
• Bacon, Boyle, Hooke, Wren, Wallis, Halle, and Newton were British.
• Tycho began his work in Denmark before moving to Prague; Romer was also Danish.
• Kepler was a southern German who did most of his work in Prague and Linz; Leibniz a northern German who studied with Huygens (see below).
• Galileo, of course, was Italian, as were Torricelli and Riccioli. Whether that's properly "western" Europe or "southern" Europe I'll leave to others.
• Descartes, Fermat, Mersenne, and the Cassinis were French. The first was educated in the Netherlands, while I think the elder Cassini was educated in Italy.
• Isaac Beeckman and Christian Huygens were Dutch and are, of course, totally neglected in the popular historiography of the period. Huygens was widely regarded as the greatest living scientist around the time of the publication of Newton's Principia.
• The Bernoullis were Swiss.

That's a rough "whos who" of 17th century science. To be sure, there's a bit of concentration at the beginning of that period in Italy and near the end of that period in England, France, and the Netherlands, and the focus of your question is about whether this concentration is real or perceived, which I can't really answer.

The standard explanation for why there is the (real or perceived) heavy concentration in England in France is that that's where the societies and journals were formed. Many of the major problems in this period derived from the difficulties with communicating science from one place to another: units of measurement and language were not standardized, and there was nowhere to go to find the the latest publication on (say) gravity. The establishment of societies and journals fixed these problems, which not only allowed for the much more rapid advance of science, but also provided the standard historical record for that we read and thus mark as "important." My impression is that science becomes much more concentrated in the 18th century, with England, Germany, and particularly France becoming real intellectual centers. But I'm not sure whether that reflects the truth or a lack of knowledge on my part.

Sources:

• Stephen Gaukroger, The Emergence of Scientific Culture

• John Heilbrun, The Sun in the Church