I think the PS4 "monopoly" also created an easier enviorment to succeed. No casual market to care of either with smartphones.
Yes this is absolutely true, last generation the market was horribly segmented. You had the Wii, which had problems selling most third party software, then you had the Playstation 3 which whilst strong in Japan, never reached the heights of the Wii nor broke into the Western markets convincingly until the end of the generation and finally we had the Xbox 360 which really struggled to sell Japanese productions.
Now we have the Playstation 4 as the console of choice in Asia, the console of choice in Europe and has a 800,000 units or so lead to the Xbox One and outselling both Microsoft's and Nintendo's consoles combined. It's monopoly has certainly helped raise Japanese publishers confidence in their own products again and we're even getting ports of their games we normally wouldn't (IE Namco porting titles like Godzilla to PS4 because of the consoles success in Japan.)
Let's also not forget how well the console is doing in Asia and in particular China. It's a good area to invest in future and I get the feeling games like Yakuza and other Japanese games are going to stay afloat to these new markets now opening.
PS4 has 70% marketshare in Europe, and Sega always performed there best.
This isn't entirely correct.
It has 70% marketshare in the UK, most European nations give it a 90% marketshare!