Can white-light LED sources produce 200+ lumens per watt?

No, the quest for higher efficacy leads to dubious, unverified claims.

Many manufacturers test their LED chips on lab benches at room temperature with short pulses – producing a high level of efficacy that cannot be achieved in practical use. While not incorrect, these claims do not reflect the typical expected output of LED sources. Reputable LED luminaire manufacturers do not base lumen measurements on the test results of their LED source suppliers, since LED chips behave differently in the real world than in an ideal laboratory setting.