Yes, but are they cheaper ?

OK, the $AUD99 'doorbuster price' bikes are cheap, and not bad value considering what you get (the finish is poor but it's very much a matter of 'never mind the quality feel the width').

But we are talking here about the absolutely most basic, unsprung, all-steel bikes here.
They price these low to get you in the store - but the more upmarket models of Huffy etc, are they any cheaper ?
You'd be surprised - similarly specified LBS bikes are usually cheaper.

And as for those fully sprung steel framed bikes - they are a very silly thing indeed.

What does more money buy ?

Frames - lighter, no difference in strength, in fact steel frames are strongest.

Wheels - stronger, which means less maintenance (truing spokes).

Bearings - longer lasting, so less maintenance.

Derailleurs - Friction shifters, the cheapest, are durable, but no good with motre than about 15 gears (you keep on slipping gears). The more expensive of the thumb shifters are more durable, less likely to select a wrong gear.

Tyres - puncture resistance, easier fit, can withstand higher pressure so less rolling resistance.

Other - carbon forks give a degree of springing to road bikes (as well as being light), front suspension so you can ride up kerbs and gives your wrists a break, fully sprung bikes (aluminium !) are more efficient and comfortable on dirt roads.