The reason why the permit matrix is different for “homebuilts” versus “ultralights” is because these have different representative organisations, who mostly don’t talk to each other
That could be a different reason? but usually “homebuilts falls under craftsmanship for the love” way more socially acceptable and encouraged nationally & internationally way more than “that foreign manufacturer now is selling 300k 200kts UL that looks like aeroplane and killing our national ULM spirit and ULM factories”
Similar story with training in Annex1, Czech CAA is happy with Zlins while DGAC is happy with Jodels, the reverse is not 100% true on non-EASA types 
I don’t think the national CAAs would have moved a single finger on this unless pressured locally.
Also what % of “homebuilts” flying were built by the owner? Various numbers posted suggest most “true kits” are abandoned and sold on, maybe sold on again, and eventually finished by someone else, then sold on several times and flown by a non-builder. Those I know about personally confirm this. Also the higher perf ones are de facto factory built; the “51%” is basically a fake. Read up the Evolution for example (various threads here) but the 200k+ high end ULs are no different.
Peter wrote:
Currently these types are bought by people who either don’t care (almost never fly abroad, or “just fly”) or don’t know (and find out after they paid for it – like one *fox owner I know).
And what kind of (relevant) limitations did this *fox owner become aware of after the purchase?
IMHO the controls are there because these types are sub-ICAO, therefore the starting point is no privileges whatsoever, but pressure on the various CAAs from national bodies had resulted in a matrix of permits. The reason why the permit matrix is different for “homebuilts” versus “ultralights” is because these have different representative organisations, who mostly don’t talk to each other
ICAO or not has nothing to do with this. EASA types such as VLA and LSA are also not ICAO, but rather EASA exclusively. ULs are in fact specified by EASA, but the specification is way too limited in scope to “equalize” EASA wide. With this 600 opt out not even MTOW is specified.
I think people talk to each other much more than you think. Often the same people have and fly all kinds of different aircraft, be it UL, experimental or “ICAO”. I’m as a good an example as anyone it’s more that people after all want to build, fly, have fun, rather than getting involved in politics.
The danger in trying to “solve” political issues, is in the way political issues normally are solved. It takes a long time, and more often than not ends up in a horse trade.
