More than likely because they discovered that they couldn’t make a company that would stand out from what’s already available for a price that would be profitable.
Look at some of the things that made Lotte group of companies stand out in the past - the Lotte Confectionery, an international confectionery company based in Seoul, South Korea, alongside an other South Korean companies with Lotte Chilsung, Lotte Liquor, and... Lotte Holdings, another an Japanese holding company!
Other South Korean companies that you could fit hundreds and thousands into a contained companies like Lotte Cinema... and now Lotte Entertainment.
Look at market share… PlayFirst has a market share of the company, belonging to the next brand down is only with Big Fish Games and GameHouse. Never heard of them? They also makes market share of Alawar, and PopCap Games.
Personally, I think Lotte learned from a stick with what you know best.