Here's some information that we need to be armed with: please correct or verify with your local mortgage lender, property inspector and real estate professionals before making this claim in your sales shcpeal.
A properly installed, properly finished on site 3/4" solid t&g wood floor adds a 200% (!!!!!!) return on the home owner's investment....
Why are you not using this statistic to educate the home owner to the value of site finished vs. prefinished engineered?
Look, I like engineered. It has a perfect value in moist areas such as below grade, but due to its not being a FLOORING, rather, like vinyl and carpeted is a FLOOR COVERING, it does not effect the property value as "real, fixed real estate"... In other words... T&G, solid wood flooring becomes a FIXED part of the real estate. It becomes part of the building and its code. It reinforces and changes the structure. Heck, it even improves the 'R' value of the home's insulation.
If a client in our market spends $10,000 on a new REAL wood floor for their property, and if the job is done CORRECTLY (ahem...) then once the dust settles, the home owner can immediately add $20,000 to the value of their real estate. Not true with FLOOR COVERINGS.
Guys, no other "home improvement", not paint, not roofing, not carpet, and (sorry) not engineered wood flooring can make this kind of return on investment.
If I offered a client in the stock market a guaranteed 200% return on investment for buying a stock, and I said that that kind of return could happen within only a few weeks, who would not buy that stock??
Think like business owners, sell like business owners, and communicate value to a good client and your sanding crews (assuming you also treat them like professionals and expect good work from them) will remain happy and busy... And if sanding and finishing becomes a lost art... We have our own ignorance and laziness to blame.

This is interesting reading. I have no reason to doubt your 200% figure. Yet in all my years in business, I don’t remember any sellers or realtors who wanted to install hardwood in order to sell the house. Refinishing the hardwood—sure. Lots of refinishing to get the existing hardwood up to par.

I could also see them having engineered installed, and saving costs on it by
either doing it themselves, or having the realtor’s all-purpose worker put it in.

But if they don’t already have hardwood to refinish, then it might be that the house is in a neighborhood where it wouldn’t make sense to invest that initial $10,000. It would be out of proportion to what the seller could expect to gain from the overall sale, even with the high return.

One question this brings up for me, is whether people who ‘flip’ houses for a living would be interested in installing hardwood. Is a good enough investment that it would make business sense for them? I have no idea, as houseflippers don’t generally contact me for any flooring services—they keep costs down by doing everything in-house.

I'd like to see you validate that 200% with some facts.

Plus I don't agree with your assessment that engineered adds no value. There's some engineered that costs more than solid, is more stable and can be sanded just as many times as any solid floor.

Just because something costs more or is engineered and more stable does not make it a "fixed part" of the real estate. A piece of 5/8 plywood with a hickory veneer on it doesn't make it flooring, it is called "floor covering" according to the housing industry.... I didn't make the rules. Read my first statement, you want validation? Then talk to your local professionals in these fields... And if you don't know any... Well it may pay dividends to you to get to know some.
Did you ever wonder why in most states that require a liscence to work in our trade make it a separate liscence? Why not keep it with carpet, vinyl, or ceramic.... Wood flooring is a separate liscence in most states because the others fall into the "floor covering" category. A covering is considered temporary..yes that includes engineered...where as solid flooring is considered permanent and a part of the building structure itself. As a permanent part of the structure, it effects the value of the structure.

In a buyers market, sellers will sometimes do what they can to increase a sale price, within the parameters of their local market (good point about creating overvalue in real estate). Recently (within the last five years) there was a housing bubble pop, I'm sure you remember. Right now in Denver there is a boom going on. A lot of buyers still remember the bubble and are trying to be a little more cautious. We are seeing homes sell on an average of within fourty eight hours on the market with a minimum of ten cash offers usually about 20% or more above asking price... NOT JOKING... Typically Denver is used to running about 14,000 homes for sale at any given time... Right now there are about 3,600 homes available...let that sink in for a minute....
So, some buyers are starting to wonder if they've paid too much and want to add instant equity to their purchase... This is what I am seeing, and my statement is just some information I provide.
I figured you might be proud of that fact rather than trash the messenger.

Uh huh, sure. You should write articles for some "floorcovering" magazines. They love blowing hot air.

Show me where it says that a nailed down or glued down engineered floor is not as permanent floor as a solid wood floor. And then you forgot the 200% thing.

IMO nothings permanent, it can all be torn out and replaced, they all wear out.