My son has an MX5 NA for seven years that got a complete overhaul a few weeks ago, new sills, etc. He loves his car very much. There is also an economic aspect. He bought the car first hand from an older lady with 120000 km after 24 years for 1,600€. Meanwhile they are sold in good condition as his is now again for more than 10.000€. On the one hand they are very popular and on the other hand very many MX5 do not survive for the reasons discussed so they will get rare.
The same will soon be true for subsequent generations of the MX5. Therefore, if I were you, I would remove all rust damage and protect the car better against corrosion than a new one was. Your MX5 will never be cheaper but much more valuable if it survives the next years with rust protection.
