Hmm, I think I know what you're trying to say, but here's the flip side of each point:
Low prices does not always equal rushed work or cut corners. Low prices can just be from an artist who even though has the skills and puts just as much effort into their work as someone who charges more, is afraid of raising prices for fear of losing customers or just doesn't realize their work is worth more than what they ask. The buyer is always taking a chance with any artist they commission from that the work won't look like what they expect - that's why it's important to research the artist before putting in for the commission.
Many artists work full time or part time jobs in addition to doing artwork. I work full time, but it doesn't affect the quality I put forth when I take a commission. If an artist is working another job they should be aware of the type of time they can dedicate to art.
Many experienced artists will still take commissions, they are just priced accordingly. That, or they are working a full time art gig in which they just wouldn't have the time or energy to put towards private commissions.
New artists deciding not to offer commissions is really their choice in what they are comfortable with. If they don't feel ready to offer their work for money and they were to try to take commissions anyway, it would hurt both the commissioner and the artist.
The sad thing is that there are plenty of people out there that expect artistic perfection on 'value budget' pricing, and the worse thing is there are skilled artists out there that are willing to give into it.