Historically, glide did conjugate like ride: the Oxford English Dictionary says it comes from "A common West Germanic strong verb" and lists the Old English forms as "glídan, glád, glidon, gliden". The Old English "long back a" vowel in the singular past tense form listed here, glád, corresponds to the modern English "long o" vowel in "glode". The Old English "short i" vowel in the plural past tense form "glidon" and the past participle "gliden" corresponds to the modern English "short i" vowel in "glid" or "glidden".
I don't think it's possible though to say whether modern dialects with "glode", "glid" or "glidden" have inherited these forms, or restored them by analogy with other "strong verbs".
It's hard to say why glide became regularized in standard English. Frequency is known to play a role in the rate of English verb regularization: less frequent verbs tend to become regular more quickly. Glide is less frequent than ride.