David Pleat first scouted Son when he was at Hamburg. The number of caps he had for South Korea not really much of an indicator of anything as South Korea is not a top league or national team.
Eriksen had good experience when we bought him - but it was from the Netherlands, then as now not regarded as a top league, nor Denmark a top national team.
I've given you as close a like for like players - but Kane for example gained the title of 'one season wonder' and even season when he made his first PL start (under Sherwood - scoring in his first 3 PL starts) there were plenty demanding he be sold, even when he started scoring.
So nothing wrong with what we are doing now. Better than buying Ndomble and Lo Celso as 'established' players. What we are doing now is to buy a selection of both younger and more established players.
First priority is probably ensuring we can sell a few layers to create space for incoming players, so I'm hoping for news on the likes of Bissouma, Richarlison and Son as well as incoming players, a number of whom I expect to be experienced 23 - 27 year olds,