Although, the geographic name Czechia was recommended for use by the relevant Czech institutions at the beginning of the modern Czech state in 1993, in a short time, it was quickly replaced by conventional political name “the Czech Republic”, almost symmetrically reflecting the negative attitude of the political elite and the population to its Czech equivalent "Česko", partially from the initial unpreparedness of national Czechs at the time of the separation of Czechoslovakia in 1993 and the preponderant indifference to the new state's name. On the sutuation praticipated long time identifying with the new state formation. By far outweighing the ratio, the opposition to the name "Česko" has not contained any rational reasons, expressing purely subjective aestheticism of "I do not like it," without any officially proposed alternative (not only linguistically and historically justified), though the condition was due to the fact that no Czech authorities distributed as they were ordered. That is why the name knows only a relatively smaller proportion of native English speakers, however, in 2016 was finally adopted as official geografic name by UN (UNGEGN, UNTERM), ISO and EU terminological style guides. Until that time, Czechia was not included in those lists and in the field “short name” was nonsensically repeated political name Czech Republic. Although the Czech name has been adopted over the years, its English translation of the above reasons still missed the broader spectrum use. Fortunately, after the standardization (since 2016), the name has been slowly spread among English speaking people, however still majority of them use that clumsy political one.
History of the problem is the core of my article “Czechia - the name dispute”, which can be found here: Czechia - the name dispute (from 2013, thus, without description of the solution in 2016)
Why Czechia in common language ?
Our country has more than 1200 years old history and only very small part of it is the history of republican system. Czechia read "check-i-ya) is a geographical name, which is independent on time and state-political changes in the country, thus, it can be used for our country both in historical and contemporary context. The Czech Republic is transient political name, which does not work in broader context and all bad consequences of incorrect universal use of it appear everywhere. It belongs to diplomatic protocol only. Only shortsighted prefers to call country by the name, which is changeable. Simply, the Czech Republic is nothing else, than the current state formation in Czechia. The name Czechia is very old, coming from Latin and has its equivalents in all languages - Chequia (ES), Chéquia (PT), Tchéquia (Brazilian PT), Tchéquie (FR), Cechia (IT), Tschechien (DE), Tjekkiet (DK), Tsjechië (NL), Tsjekkia (NO), Tjeckien (SE), Cehia (RO), Çekya (TR), Češka / Чешка (HR, RS), Чехия (RU, BG), Чехія (UA, BY), Τσεχία (GR), etc. Why English should be only exception?