So you paid about 1 days wages for it 5 years ago and now it needs a new $ 30 starter.
I don't see a problem with that.
If you want a mower to go 20 years without any failure you are living in lar lar land.
A commercial grade mower might come near that but they cost about what most expect to buy a ride on for now days.
So yes you will need to buy a new starter.
The cost of warehousings & logistics + invoicing individual starter parts now days is 4 times the gross mark up and that is before the workshop charges 1/4 hour labour so almost no mower company still supplies individual starter parts.
Even replacing a starter rope is a loss making enterprise as I charge $ 10 and by the time you pull the starter off . Clean the debris out from around there , get a new rope , wind it in and knott it off 15 to 20 minutes have passes , 10 of which are not charged for.