It was really cool! The ease of getting started was definitely one of the selling points for the “home computers” of that era (GW-BASIC ran on IBM compatible PCs instead, but the appeal of BASIC was the same). Brevity was an important feature since a lot of people obtained programs by typing them over from a magazine or recording them from the radio. And of course, there was no such thing as auto-complete (let alone AI generation).
That being said, SDL isn't actually that bad either. A minimal example is about 40 lines of code [1], not counting comments and blank lines, but including lines with just a curly brace which you could easily remove if you were concerned about size. A slightly more serious implementation of Snake runs about 345 lines of code [2].
And to be fair, DONKEY.BAS is also cheating slightly on the line metric by stuffing lines full of statements, like for example:
A$=INKEY$:IF A$=CHR$(27) THEN 1298 ELSE POKE 106,0:IF LEN(A$)>0 THEN LINE (CX,CY)-(CX+28,CY+44),0,BF:CX=252-CX:PUT (CX,CY),CAR%,PRESET:SOUND 200,1