English term (edited): please do not squash :-)) je n'arrive pas à traduire la dernière phrase entre **

Je viens d'arriver dans le débat - voici mes quelques réflexions, à voir si ça vous aide ! : the usual phrase is 'it's the tail wagging the dog' (instead of the natural way round !). It's not really a pun - it's a metaphor, comme (style titre d'actualité ;Published on Wednesday, October 13, 2004 by the Toronto Star
Israeli Tail Wags American Dog", although there's a web definition of the recent business term 'long tail' = "when you give people millions of choices—in movies, or other consumables—then create a graph, where the available choices are plotted (in descending order of popularity) .....the result is a swooping line with a "long tail." In other words, a relatively small percentage of the available items will be very popular, but most of the items available will receive little use".
To me your writer is saying that the doubt about such broad spectrum ('éclaté' ?) investment in advertising on all these fronts is perhaps unfounded and is in fact worthwhile.
"Donc venez écouter ...pourquoi des investissements si éclatés peuvent en fin de compte se justifier / faire l'affaire / faire ses preuves / (ou pour reprendre la tournure négative) "ne sont pas forcément une abérration (un peu fort, mais est-ce que mes idées vous aident un peu ?)