SEO Refactor ecommerce site from selling in one state to multi-state

Hello,

I have an SEO question about an existing successful ecommerce website that I manage that has achieved some very high Google organic search rankings for many highly competitive keywords, relating to the sale of some products in New York State, and would greatly appreciate your advice.

To avoid any claim that I am trying to promote the actual website by posting this question, I will refer to a hypothetical domain name and company industry.

This question does not pertain to paid ads or landing pages for paid ads... only to Google organic search results.

The fictitious domain name is: buyshoes.com and it sells shoes to the public on its ecommerce website.

The website has been live for about 2 years.

When the website was originally conceived, the target market was to sell its products only to people who live in New York State. It was not contemplated that the website might one day also be used to sell shoes to people who live in other U.S. states. Therefore, the homepage and its meta description tag and title tag, and almost every other page in the website specifically mentions New York State and locations in New York.

The site's homepage currently ranks very high in Google organic search for our targeted keywords for New York search results. Most of the backlinks for the site point to the homepage. The current homepage converts users into purchasers very well.

The situation we now encounter, is that we want to start selling our products to people in other states. Due to the nature of our products, the products will have unique characteristics for each U.S. state that they will be sold in.

So, the end state of redesigning the site would be that the common user experience that the homepage would only refer generically to "selling shoes" and we would add a way on the homepage for the user to select which U.S. state they live in to buy shoes, and then we would build a separate product page for each U.S. State with the directory structure: buyshoes.com/state/new-york/productName buyshoes.com/state/new-jersey/productName etc. Each product page will be highly optimized (SEO) for the U.S. State in which the product is sold.

My SEO question:

If we refactor the homepage as described above so that it no longer mentions (anywhere) anything relating to New York State (e.g, remove all references to the words New York, NY, NYC etc) and create a new screen for products sold in New York State (and move all of the New York related content from the existing homepage to the new New York state specific page), what will happen to the website's organic search rankings when users search for our targeted New York state keywords, e.g, buy shoes in New York?

Will the new page for New York products acquire the same high rankings in the Google organic search results that the homepage previously ranked for? If yes, how long do you estimate it will take Google to swap the ranking of the homepage for the ranking of the new New York State page?

I am very familiar with the SEO ramifications of "replacing or renaming" an existing page with a new page with 301 or 302 redirects. However, that is not the situation I am now confronting (leaving the existing page in existence, and merely moving all of the targeted non-generic keywords from the existing page to a new page).

Google indexes our site daily and I know that it can take Google days, weeks or months to attribute the highest possible organic search ranking to a page as a result of its onsite and offsite SEO.

Assume we rolled out this major change to the site today, my hope would be that at some point, (days? weeks?) that the new page for New York products would simply replace the site's homepage in the Google organic search results for New York searches without losing any of its ranking. Do you think this is what will happen?

Naturally, I am most concerned that after we roll out this major change to our website, that Google may not simply replace displaying our homepage with the new page for New York products with the same search ranking, and we might completely or significantly lose our high search result rankings for our products sold in New York State. (for the purpose of this question, assume that we will not have new quality/authoritative backlinks to the new page for New York products for at least several weeks or more).

While it is great that we have used all white hat SEO over a year or so to finally achieve very high Google organic search results for our targeted keywords for our products sold in New York State, we are very concerned that we may lose these rankings if we expand our business and refactor our website as described in this question.

Naturally, I would love to hear from anyone who has gone through a similar website redesign as to how it affected their organic search results (in the short term and long term), but all feedback, advice and suggestions would be greatly appreciated!

Thank you for your insights, help and suggestions!
JB