One shouldn't make an all dextrose starter because it's not nutritionally complete; it lacks vitamins, minerals, lipids, amino acids and nitrogen the yeast need. All it would provide is carbon and energy.
Yeast also don't get "lazy"; they switch off genes they're not using. They then switch them back on later, as needed. If later is very long, there can be some genetic drift, but that would be over dozens of re-culturing steps, if at all.
Depending on temperature, some specifics of the strain, etc. it'll take at least two hours or more to switch the relevant gene, MAL
, on and have the maltase enzyme accumulate to an appreciable amount. That's two or more extra hours that your wort isn't guarded by active fermentation.
That's why you should grow in malt!
I routinely grow yeast on YEPD agar plates and then YEPD liquid for the first step up; the actual starter is malt at about 1.050 or so, supplemented with some yeast nutrient for wine making, it adds nitrogen.
YEPD = Yeast Extract, Peptone, and Dextrose. Peptone is digested meat, a good amino acid and nitrogen source.