the should do a mk game like Sonic mega collection

I think the most likely reason there is no MK collection package is a simple one, money. MK is nowhere near as big as it once was, and I guess the Midway marketing team don't see much profit in this. It probably works better for them to include a couple of MK games on an MAT package, as it has more chance of enticing the non MK fans with other games, as well as MK fans wanting to play classics. Sadly, the marketing guys are always going to think of profits first.

in xbox sky (a bittorrent website for xbox) there is a collection made by a fan that has the arcade ports (not emulator) of mk1 mk2 and mk3 in one CD (its about 256 mb when ziped) and that is as close as we get

Yeah, you're right, MK isn't as big as it once was. No wonder Deception is the best-selling MK game of all time and Midway's best-selling game of all time, hmm?

There is no way MKD is the biggest selling MK of all time. I wouldn't even rate it close. Even MKDA was a better seller than MKD, and I don't think that sold as well as the first three MK's. MKDA sold at least twice as well in it's first year as MKD managed in it's first year. It probably sold OK, not especially brilliant but good enough in the States, where most MK fans are, but was a bit of a flop worldwide.

For a start, the figures Midway give to hype up the games sales tend to be the "units shipped". This isn't the same as sales, these are the games sent to the suppliers, the stores. After about a month, most stores were selling MKD new at cut price. MKD may have won a handful of bullshit awards that might as well be "Wal Mart award for best game with a ninja named Scorpion in 2004". The only reason it won best beat em up awards in 2004 was that there was nothing else new to compete against it that year. Games reveiwers who know their stuff gave it generally mediocore scores at best.

Even the most blinkered MK fanboy has to admit that the fanbase is nowhere near as big as it once was. MKD had nowhere near the mass media coverage of the classic games. The first two MK's were groundbreaking, and paved the way for more adult themed videogames. These games had worldwide attention, and importantly, also from non gamers. MKD can't even dream of getting this hype. MK hasn't quite recovered from it's late 90's slump, and MKD failed completely to build on what MKDA started to do, make the series at least a credible contender again, in sales if not especially in gameplay, to games like Tekken and Street Fighter.