In the quest for sales, bow companies usually have to make at least a little gain in speed. Over the years, bow companies have exploited cam designs with different draw force curves and let off. Then when there wasn't much more to extract out of cam designs, they started honing in on ATA. Shortening a bow 1 inch is 3 fps gain in speed. With all being equal, a 30" ATA bow is 30 FPS faster than a 40" bow. Bow companies have slowly shortened the bows over a 20+ year period to keep making faster bows each year to generate sales.
In fact, the parallel limb bow is a bi-product of making shorter ATA bows. You can only go down to about 34"-35" with a non-parallel bow design. The riser will be too short and there isn't enough room for the grip and sight window. To combat this issue, the parallel limb bow design was put into the works. A parallel limb bow design allows for the riser to remain long while the ATA can be shortened. The fact that a parallel bow design has opposing limb movement that cancel out each other's momentum is a bonus.
Now that bows have gotten down to the 28"-30" ATA, that avenue for performance is about exhausted. Once the bow's ATA is around the length of a hunting arrow, going any shorter isn't going to have a benefit. The bow is only as short as its longest component. The average draw length is 28" making the average arrow around 27+" plus the length of the broadhead making it around 28+". Making a bow any shorter is of no benefit.
Now bow companies have turned their attention to the brace height. It was common back when bows first started getting shorter to design the bow with a longer brace height to help keep the bow more shooter friendly. But if you can reduce the brace height 1", it gains about 10 FPS in speed. So, bow companies have been shortening the brace height of bows over the last few years until most of the hunting bows are 5.5" to 6.5" range.
The perfect bow design would be to have the valley of the grip in the center of the bow and also have the arrow nocked in the center of the bow. But unless you have hole in your hand, that isn't going to happen. Some companies, like Mathews, have went with putting the arrow in the center. This makes for a bow that is more top heavy and takes some getting use to. Some companies, in the past, have put the grip in the center of the bow. This creates a challenge for designing a tune-able bow. Most companies just split the difference with the grip a little below center and the arrow a little above center make for a great compromise.
With most bow companies now using some form of a binary cam system, this makes it easier to keeps bows shoot-able and tune-able. The binary cam system locks both cams together in a figure 8 and no matter where you pull on the string, both cams move at the same time.
Binary cams are a 2-cam design. There has only ever been either a 2 cam or 1 cam design. The "cam 1/2" is a modified single cam design. With today's bow designs, the binary, having symmetrical cams, is going to be the most utilized design going forward.
You look at Mathews new "bridge-lock" design and may think it is a "new" technology developed by Mathews. But it is just a fix to a problem they created. With the Mathes riser being overly long, they had to beef it up by bridging it wider. This wider riser created an issue. Once the rest and sight were mounted to the side of the riser, this pushed the quiver out even further making the bow cant over to the side. To fix this, the cut a hole thru the riser and eliminated the sight mounting to the side of the riser and they mounted the rest to the back of the riser. This allows for the quiver to be mounted closer to the riser improving the balance. As for having a mounting block machined into the riser, High Country Archery done that back in the mid 90's so the technology isn't new. Mathews just reinvented the wheel and with good marketing sold it to the hunters. Then they also done it with stabilizers.
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