Something like 63% of All-Pro and Pro-Bowl OL are drafted in the 1st round. Then like 16% or so are drafted in the 2nd. It's clear that you find the best OL in the upper rounds of the draft. And that's not unusual since you would expect the best players at any position to be drafted high. Some you can get lower because they are devalued positions like S, RB, and to some extent LB (not EDGE rushing LBs), but that is not the case with OT.
Some teams get lucks and manage to get good OL in later rounds, but those are the exceptions, not the rule.
A team shouldn't force an OL pick early in a draft if the value isn't right, but it would be dumb to just decide not to take OL high in drafts under any circumstances.
