I think it's pretty much guaranteed that it's going to happen.  This generation is going to last longer for the Switch than normal because of chip shortages.  Also software sales continue to increase each year, and so do the number of titles released.  Nintendo is releasing so much software right now, that they aren't going to replace the Switch any time soon, and even when they do it will still sell decently for a few years even after the successor releases.  Also, Switch hasn't even had a price cut yet.  There are so many reasons why it's just going to keep selling.

I was expecting a Switch 2 release on March 2024, but now, I can see a new console most likely on March 2025. 

Nintendo is going to do a price cut when Switch production supasses demand, and even before that we can expect new bundles with free games.

Nintendo has all the damn cards: New Bundles, Price Cut, Unnanunced 2023/2024 Games from all the studios for one console ready for a future Nintendo Direct.

At this point, a Spring 2023 successor will not happen or it would have already been announced formally.

Nintendo DS announced November 2003 and releases November 2004

Nintendo Wii announced (as Revolution) in 2004, released 2006.

Nintendo 3DS announced March of 2010 and released February 2011

Nintendo Wii U announced in April 2011 (as Wii successor), shown during E3 2011, released in 2012

Nintendo Switch announced as NX in 2015, in April 2016 they stated they planned to launch the system March of 2017, October 2016 they unveiled the console. 

Basically, Nintendo would have given us at the minimum a codename or an official announcement other than "we are always working on new hardware"

I hope the Switch successor isn't until 2024 personally, but this is Nintendo and they're anything but predictable, so I don't feel secure in ruling out a 2023 replacement at this point.
Like most systems replaced in recent years, (3DS, PS4, Xbox One) I don't think many Switches will be made once the successor hits shelves.

Just a heads up. The next VGChartz hardware update for the week ending April 30, 2022 will be delayed to later this week. I am waiting on data (Famitsu for Japan), as well as for Sony and Nintendo's earnings report for Q1 2022 that will come out tomorrow.

I'll make the necessary adjustments to our PS5 and Switch estimates based on the latest shipment figures. 

Here is the preliminary data for week ending April 30, 2022:

• Switch will likely be relatively flat in the US and Europe week-on-week.
• Xbox Series X|S will be up in the US and flat in Europe WoW.
• PS5 will be down in the US and up in Europe WoW.

With April NPD releasing tomorrow morning, I plan on posting the VGChartz estimates for week ending April 30 tomorrow after I make adjustments in the US based on NPD's report.

With the data we have, the PS5 had a great final week of April in Europe. The Switch saw a minor boost due to the release of Switch Sports in most regions. All consoles saw a boost in Japan. Xbox Series X|S sales remain relatively stable or up slightly.