Why can't PS be more like LR ?

Question

I somehow had the impression that one could use PS CS5/6 in much the same way as Lightroom, in respect of 'continuous editing'.
In LR, if I close and restart, my situation is exactly as if I had stayed continuously open. I can backtrack, do whatever I could have done if I had not closed down (and even rebooted). The basic situation in LR is that one is always looking at the same photo with all the editing steps applied, but all the steps undo-able.
I thought that if I saved in PS as a PSD file, it would be the same, but of course, it is not.
Is there a mode for operating and saving files in PS in similare or same way as LR ?
If not, why on earth not ? LR is on version 4.3, so, although PS is a more mature product, there has been plenty of time for this desirable operation to be integrated.
I have been doing some work with PS which I really would like to have been able to go back on, but I now have the choice of staying with what I have got or going back to the original LR export and starting again. I also thought that using smart objects would do the trick, but first it limits what one can do and second only the layers seem to be saved and not the history.
Mind you, as I am not a PS or LR geek, I am probably missing something which is staring me in the face....

Answer 1

Hmm, thanks for the links, C.P. I would have been more surprised if I had been the first to think this would be desirable.
We can all have our view as to desirability, but the option to click a box or two in preferences would seem to satisfy both worlds? As to massive waste of resources... I dont think storing history would require much at all. Masks are stored as just a value of 0 or 1 for each pixel in the mask and thus not 24/48 bits per pixel like layers and transient images. But brush strokes are another problem, they would need 8 bits per pixel, still not a lot in modern storage availability.
(I have 24GB memory, 12-core i7 and about 3 TB of disk space -- so I have a different view of memory and such, so I would tick the boxes in preferences.)
With smart objects, or with 16bit/px images, some things are greyed-out as not available. Surely, an intermediate ground could be found, so that if one has the history storage facility turned on some features would not be available?
There are a lot of features in PS that I do not want to use and cannot imagine the use people put them to, but I don't feel they should be removed just because I dont like them.
What I DO find is that I might spend a long time working on something and I decide that the latest things I did are not to my liking. If I have not stepped out of PS, I am ok, but otherwise, I have lost it, and it is back to the beginning. I do not belong to the linear, organized, part of mankind, hence my question and preference.
I find JJM's contribution helpful, so obviously a good idea, and one I may well adopt.