where would their times have got them in todays athletics?

This should answer your question: http://www.youtube.com/watch?v=_L_vq5JYQlE

They'd be pretty good ... for high school athletes.

If they ran their 1924 Olympic finals times in the most recent California state high school championships:

Abrahams would've come in 3rd or 4th (behind one Sophomore)
Liddell would've come in 8th.

And that's without adjusting for the fact the 1924 times were (I think) hand-timed, which tends be a little faster.

But if they were running today they would have been coached in modern running styles don't you think?

"They who... give up... liberty to obtain... safety, deserve neither liberty nor safety."

So many things are different between then and now that it's impossible to compare apples to apples. Shoe technology has advanced dramatically since then; track conditions are worlds apart -- in the early 1900s, they ran on outdoor dirt and gravel tracks whereas today, they run on indoor and outdoor synthetic tracks made of a firm, springy rubber; 1900s sprinters had to dig their own toe holds, in dirt(!), for the start while today's runners have the advantage of rigid appliances that are fixed to the track surface; even their attire can make a difference, with today's runners wearing lighter, thinner fabric that is less restrictive. Not to mention that athletic training is serious business these days with many training regimens being perfected through scientific testing. No doubt track stars of the past would benefit greatly if they had access to today's track-and-field advances in both technology and training techniques.

Then, of course, there is the matter of today's "performance enhancing" substances -- some legal, most not but which are used anyway -- that tip the scales in favor of modern runners.

Not very likely, since steroid use wasn't prevalant back then.

Hard to say how fast; lots of factors.

1924 negative factors:

The track surface - cinder tracks quite a bit slower than today's lightening fast mondo tracks.

Spikes - heavier; not aerodynamically designed for speed and fit

Starting blocks - not used in 1924

Apparel - wore loose fitting singlets and shorts compared to aerodynamically tight fitted, one piece speedsuits.

Training, health and diet - Overall less sophisticated and scientific, however no fast food temptation.

1924 plus factors:

No FAT (Fully Auto Timing), races were hand timed which the standard reading is .24 seconds faster than FAT. So an HT time of 10.0 would be 10.24 FAT

1924 Unknown

Wind readings - wind readings were not available. It's unknown if times recorded were assisted or hindered by wind in 1924.

Evolution of the human species - Humans are bigger, stronger and faster simply by each generations DNA passed on after increasing the workload will create a stronger individual the next generation.

OP, there’s a wonderful history book that you would enjoy, titled Fast Tracks: The History of Distance Running Since 884 B.C. That is, if you want a serious comprehension of every factor that contributes to a real answer to your question.

If it’s just an idle question, don’t bother. You’ve no idea how complex the answer is, including the psychological aspects of world-class running.