This is exactly why I've abstracted my Gmail accounts behind my own personal domain. If Gmail starts charging/gets shut down/I get tired of it, I can switch over to another email provider that supports custom MX domains.

I (almost [1]) never use my actual Gmail address.

[1] The only time I use it is for Google services (i.e. Adsense) that require a Gmail account.

That's why you use Google Apps for Domain with a domain name you have control over. That way you can switch providers but keep the same email address.