I think over the last 20 years there have been 1 or maybe 2 trials for European or World Championships -
Are you just quoting from your memory over the past 20 years, or have you simply been to the main countries website to check out the selection policy?
Over my time at TTD, it doesn't seem like much forum members knows much on the background in Europe national body structures.
Of the European languages, I only speak English, I first went TT England website to check:
This is for WTTC 2019:
https://tabletennisengland.co.uk/wp-content/uploads/2015/10/World-Championships-2019-v.1.0.pdf
4. Criteria
Selection can be achieved either automatically or as a wild card by the Selection Panel, as
follows:
a) Automatic Selection
Eligible athletes will gain automatic selection, subject to compliance with the rest of this
policy, if they meet one or more of the following criteria:
i. hold a top-100 ITTF senior ranking for two or more months within the qualification
period;
ii. The current English National Singles Champion as at the conclusion of the
qualification period.
In the event there are more automatic selections than places, places will be offered to
eligible players in ITTF ranking order on the most recent ITTF ranking list available at the
conclusion of the qualification period (not the selection panel meeting date).
In the event that an athlete meets both criteria, point i will be accepted first and no
further places will be offered to beaten finalists or other players within point ii.
Please help yourself (if you know more than English) to check other main countries out
https://www.ettu.org/en/about-ettu/member-associations/
I found an English portal for Belgium, but couldn't find any source for selection
German, Denmark, French didn't have English options
I think Jesperstef, the key is there is 2 kinds of entry to these tournaments:
1) self selection - if you do well in trials, or you do well in national championship (by winning), or do you well in world ranking. Mean the player have full control of his/her own fate
2) coaches selection - this is wild card selection - and this is where maybe your best player is injured for the year and has low ranking, bad or no result in world tours/national champ etc but should go with the team.