No format or camera is universally best, and this will always be true. For people people p&s makes the most sense. For some, mirror less. For others, SLRs, medium format, large format, and so on. You can make a list of pros and cons for each format, or make lists of why x format is better/worse the y etc.
The SLR is the sweet spot in terms of performance, versatility, and portability. At the end of the day, its limitations are minor compared to what you'd give up to use a different format. For example, if I wanted to gain a little portability by using a mirrorless, I'd be giving up on tilt-shift, optical viewfinder, AF performance, subject isolation, and image quality. I can think of many reasons why this trade off would be worth it, any many reasons why it wouldn't. In another example, if I chose medium format, I'd be giving up on AF performance, portability, and low light performance, but I'd be gaining image quality and n flash sync.
The DSLR is the jack of all trades, throw a pancake on it and call it a p&s, anything-you-can-do-it-can-do almost as good or better.
Maybe in ten years mirrorless will advance to the point where it can obsolesce the DSLR as the jack of all trades, but like the TLR or the rangefinder, the SLR will always have niche applications and enthusiasts.