As presented, those "basic" rules are 180 pages. You wouldn't lose much by cutting down the levels.
On the cleric you'd only save 2 or 5 paragraphs by stopping at 14th or 3rd, respectively. So somewhere between 1/4 and 1/2 a page. For the fighter you'd save 7 paragraphs by cutting things down to 3rd level...which is about 1/2 a page. The rogue, 11 paragraphs, so somewhere between 1/2 and a full page. The wizard saves about 11 paragraphs if the basic rules are cut down to 3rd level and saves 4 paragraphs if cut down to 14th level.
Spells you'd lose pages. At 3rd level you can cast 2nd-level spells, at 14th level you can cast 7th-level spells. You'd save about 12 1/2 pages if the game stopped at 3rd level. You'd save a few pages by stopping at 14th level as there's only 16 spells of 8th or 9th level...being generous let's say that's 5 pages.
Monsters are iffy at best. It depends on how the referee runs things. Do you need a CR17 dragon if your PCs can only go to 3rd level? Yes, because dragons still exist in the world regardless of the PCs' level. No, because at that point dragons are a plot point rather than a creature to fight.
So these "basic" rules would be about 164 1/2 pages long if they only went to 3rd level. So a total savings of 15 1/2 pages. Wow. That's so much shorter.
Augh! I have work to finish! Don't make me try it to find out!