Surely both the age and continued speculation of a new offering in the series has a negative impact on sales.
Why buy a Switch when a Switch2 might be just around the corner?
However in 2024 the portable gaming device market could not be better for gamers with attractive devices from multiple OEM's and many price points.
Granted most/many of the device options are now >$400 and even >$600 Nintendo has its work cut out for them to remain competitive in 2024 and beyond.