Today's small power air forces probably have the feeling of doing the equivalent of preparing for the Second World War with biplanes - and don't like it.
The "4th" and "5th" generation fighter distinction may be mere marketing or not - plenty has changed in combat aircraft technology during the last two decades, and 30+ year old designs such as the Gripen kind of feel like 2nd class: Fine trainers and useful against inferior opposition, but unlikely to prove useful against great power air forces in the future.
|KAI concept of a T-50-based LO light fighter|
South Korea may be up to something really smart; a fighter which incorporates the new style at least partially, but is still modest enough to be affordable in quantity (that's the hope). The Europeans have only modern combat aircraft designs rooted in the 1980's (Typhoon, Rafale, Gripens), Russia and China aren't satisfactory suppliers to many countries (such as South Korea) and the U.S. has only a not yet finished, but already very expensive ground attack aircraft with an untested approach towards air combat on offer (F-35).
The concentration in aerospace industries and the exponential cost growth for combat aircraft development have lead to a world with very few combat aircraft designs. China works hard on adding to the list, but that's not reassuring to certain countries. Back in the 1960's a bloc-free country had the choice between plenty combat aircraft.
A list of 1960's supersonic fighters in production:
Freedom Fighter (F-5A/B)
Today a small power can buy designs rooted in the 70's or 80's or equivalents only. It's a very unsatisfactory situation for some air forces.
*: I ignored Thunderchief, several specialised interceptors and the during the 60's obsolete first supersonic generation (MiG-19, Super Sabre, Super Mystère, Tiger). You need to draw the line somewhere..