If the proper steps are taken it can be stained successfully. Now if done right it doesnt stain like oak for example. Stained maple has a unique look. Blotchy but not bad. Its hard for me to describe without writing a novel.

Others here have experience with dyes and tints. I only stain. You dont need much color to get both the new and old to hide the age difference.

Get your guy to show you some samples on your floor.

Look at the Bona Amber Seal as a first coat. We used it on our birsdseye maple floors and it very nicely popped the figure without overly darkening the floor. You can apply two coats for more color. It's much easier to use than a stain, no evidence of blotching.

The floor guy is getting us a sample of a stain on our wood. I will also ask if he can get a sample of the Amber Seal. I did a little research, and it looks intriguing. Thanks for your advice.

Amber Seal is just slightly darker than natural and is intended to give floor the look of floors finished with oil modified polyurethane.
Maple is a closed grain wood so in most areas the stain doesn't penetrate well and in some areas it does, leading to the blotchy look mentioned above.
The best way to even out stain on Maple is to apply a coat of water before applying the stain. This makes the wood fuzzy (for lack of a better term) allowing for better stain absorption. I would recommend you pick out a color from a stain chart (which is usually show on Oak) and have your finisher make a Maple sample where half is pre-coated with water and the other half is not, then apply the stain and finish. The water popping will make the floor darker so you might need to go to a lighter color or mix some neutral with the stain you initially select. Another method would be to go to a home store that sells samples and buy a small sample of something you like, to help guide your finisher. He doesn't want to waste his time and money making samples that are nowhere near what you want and you'll likely reach a color choice more quickly this way. Of course you probably already know that you're limited by your wood so he won't be able to make your floor look like Walnut or Brazilian Cherry.

@gregmills_gw, came across this while searching Bona sealer for maple floors. What did you end up doing for your maple floors? Can you please share the details and pics if possible? Thanks!!