I have not known at any time when parts have high prices (typically on proprietary parts, that the me too parts houses haven't had time to back engineer)) on certain items or on back order for any brand, model or type of equipment and age (new or used).
But this is my opinion based on 41 years of experience in the industry and like navels every one has an opinion - you have yours, I have mine - I am sharing my opinion with you - you have a choice think about or not. But customer's, with cash or at least that pay their invoices, are king and dealers need to take care of them some how some way. Certainly factories need to treat their dealers as customer too & have been known to take parts off of new equipment inventory to keep the dealers end user happy. I've carried parts through airports (before 9/11) or in the trunk of my car to keep customer satisfied. An old business theorem is you will loose 10% of your current customers/employees every year no matter what you do holds true today. It is a lot easier to work to keep them than let them go down the street. Then it takes ions to get them back. Life is full of choices & risks.