Not many teams are scheduling the top of FCS when they schedule FCS. If we're going to knock scheduling here on this thread (which is precisely what prompted this discussion), then it's perfectly reasonable to knock scheduling FCS teams.
I think a lot of FCS scheduling is geographic more than based on team quality.
I don't know how many years in advance most FCS teams get contracted to play paycheck games, but the other aspect is that like a lot of scheduling, you may try to schedule a good FCS team and by the time you play them, they suck, or you try to schedule a local FCS team who sucks and by the time you play them, they're good.
Purdue already has Southern Illinois on the slate for 2025, Indiana State in 2026, all 3 OOC FBS in 2027, Western Illinois in 2028, and hasn't filled out their OOC slate beyond that (although has two FBS already for 2029).
Obviously with Purdue playing Illinois and Indiana teams it's mostly geographic. But while I don't know when 2025 was scheduled, I don't think any of us can predict what 2026 ISU or 2028 WIU will look like based on their rosters today.
Where I'll agree with you is that a team like Purdue isn't going to be seeking out some "traditional FCS powerhouse" to the extent such things exist... I don't see them putting someone like Appy State in their heyday or SDSU now on the schedule. For a team like Purdue, that's all downside. A win doesn't look all that impressive, but a loss looks terrible.