Themselves. They're able to shoot themselves in the foot at the weirdest times. Otherwise, I would say new players, because Xbox will most likely never beat PS (except if Sony screws up even more than the PS3 launch).

I disagree with the "they follow proven trails" because of Move. Sony did the CD console first, the motion gaming with Eye Toy before the Wii, the remote gaming with PSP and Vita, VR with PSVR and also the streaming gaming service (PS Now) long before MS or Google. They also have a TV service, no? PS Vue ? They usually do things first in the console field actually, even if they don't always use it fully or find huge success with it (and you end up with "The Wii invented motion gaming!" even though you had motion gaming on PS2). 

Hard to answer.

As for their biggest competitor, I'd say: In Japan, definitely Nintendo. In Europe, I'd say PC. In North America, Xbox and Nintendo share that spot.

However, as for the biggest threat, I would say mobile gaming. And that's not just for Sony, but also for Xbox, PC and Nintendo.

Case of point: I gave my nephew my Switch and Super Mario Bros 3 to play. He didn't like it. I thought it was because of the outdated graphics, but he answered that it is too complicated. And yeah, he died 3 times against the same first Goomba, both in SMB3 and in SMB (which he did dislike because of the outdated graphics btw). I gave him the Dragon Quest Builders demo, but he couldn't figure out the controls and couldn't leave the first room as a result. Ironically maybe, he's very good at Snipperclips Plus instead. My wife, who never played Videogames outside of her Smartphone before, plays Super Mario Kart 8 Deluxe, but zigzags more than a sleepy drunkard. She's just unable to understand that the kart will drive forwards by itself without any input from the player (and no, she doesn't have a driver's license!)

They, and probably a whole Generation along with them, are more used to play things like Hungry Shark, Hay Day or some Match-3 clones. Things that don't need any effort or are just puzzles. Console or PC games need a minimum of effort an rarely are just puzzles, and thus seem to much already for them. Unless we can teach them how to play and what makes a good video game, I fear the market for consoles and PC gaming will shrink in the coming years.

Rol will be back in a few days. 

I dont agree the 3ds is or was the main ps4 rival. Yes sales were decent but the console had very little impact on the ps4. The biggest would be having the monster Hunter ip for the first few years of the ps4 life. 

Mostly Sony out of the ones listed ...

They're not dominant in Japan or portables but that's going to change in the not too distant future when streaming gets better and when competition heats up from mobile as well so that's a market inevitably in decline due to demographics or becoming more crowded ...

MS as they have the potential to steal the customers and have the eco-system in place to do so.

Its MS because the western core market.

The audience Nintendo really competes with Sony is Japanese content, which is a smaller market. Nintendo primarily thrives on 1st party content, not content it shares with a competitor.

Ultimately, MS and Sony primarily chase the same audience and do so with similar machines and libraries. They react to each other.

Right now, I would say Microsoft now that they're gearing up to give it all at the next E3. They're looking to take back the big piece of market Sony took from them at the beginning of this generation, and they'll likely take a sizable chunk if not a huge one.

Double post, sorry. Please delete this post

I wonder who made touchscreen/gyro censor/microphone on handheld first? Sony?

This.    

 Nintendo gave up on Home Consoles, and I can't see MS as a threat. In NA it will be a good competitor though.