I think this shows more a change in Playmobil's marketing policy, introducing short-lived themes alongside the long lasting "standards".
It's not a change in marketing policy. They couldn't afford that. All the cost for research and development and mould making and packaging and advertising, etc, et al. Then to have flops. Year after year. Romans, Egyptians, Ghost Pirates. All themes I love. All one I would have loved to have had when I was a kid. All themes 'collectors' raved about. Yet, they flopped.
No company can afford short lived lines UNLESS they sell a LOT of them.
Playmobil has not sold a lot of any of these themes. As evidenced by shop supplies and the products that are being resold at discount prices on the Playmobil sites - they have a back log of warehouse stock they have to get rid of somehow.
Future flops will be the cavemen and the 'future' theme.
I don't know about the Secret Agent theme. Time will tell on that one.
If, after these, anyone thinks Playmobil will try historical themes again (ie Greeks, Japanese, Persians, etc) they are in for a sore disappointment. It's not that we, as adults didn't buy the sets - it's pretty obvious we did (and do) - it's that the real market, children and their parents, did not want these.
I think it's a sad reflection of today's society and societal interests as a whole.
In the past, before video games, there were markets for children of ALL ages - all the way up through and including teenage years. Now the toy market is aimed at very young children only. There are no toys for children past the age of 8. Go ask in any hobby shop how many teenagers have come in (if you can find a hobby shop that is still open).