I love my primes... and I shot with a 50mm f1.8 for a year or two as my primary lens... but I'm not sure on what planet someone buys a 24 mm lens as their primary do it all lens alone. No zooms... no other primes... no flashes.
And I realize what sites through the view finder is comparable... but if you give me as a beginner a pile of cash... I don't think I will go out and buy a 24mm prime.
There are many. X100 has 35mm equivalent lens and people love it . EOS-M has 22mm prime lens which is 35mm equivalent too. I'm using 40STM pancake a lot and it is very close to 35mm. It is a very popular standard focal length. I agree that 24L is not the lens to begin with on crop (huge, heavy, expensive), but for "glass before body" kind of thinking it may be an option.
With that 1700 I can get a combination of the following depending on what I want to shoot:
Canon 24-70 f2.8L
Sigma 35 art
Canon 50mm f1.4
A 100mm f2.8L is
A 135 f2L
A 70-200 f4L IS
A 430 or 580 ex speedlite...
Mix and match as much as you like... and you will have greater flexibility in your photographic efforts. True the images will not be quite as nice as a full frame alternative.
Ok, but I choose quality over quantity. I don't need to "cover the range" and it is only one L lens less for FF, really. What you'd get from your list on APSC is:
A 160/4.5 IS
A 112-320/6.3 IS
Nothing impressive for the price . I have a friend who decided to add a FF camera, so he would have twice more camera/lens combinations with his current lens collection (L zooms mostly), but now I see that he is not using his 550D anymore. 5D3 is so much better, he says . Now I have to convince him to shoot RAW .
I might be doing a disservice to the 24mm, but it isn't about the individual maximization of the images as much add having the tools to get the images... and a crop will get you there until you have the coin for full frame.
I feel as though I missing something that needs to be said...
Also... I don't like the math of your example.
That's just one of many possible examples, like FF+85/1.8USM vs Crop+50L, or FF+135L vs Crop+85L
2650 for the 6d and the 35...
2150ish for the t2i and the 24mm...
Well, you can get a used 5D2 for as low as 1k these days. My point is that you can get a much better combo for just a few hundred $ extra.
Let's knock off 500 from the full frame option and we are looking at a 35 f2 is.. and suddenly image quality starts to even out...