Lots of metrics are missing from Thanos

Lots of metrics are missing from Thanos are present:

For example, compare these two queries, in Prometheus and Thanos:

https://prometheus.gprd.gitlab.net/graph?g0.range_input=14d&g0.expr=slo_observation_status&g0.tab=0

vs

https://thanos-query.ops.gitlab.net/graph?g0.range_input=14d&g0.max_source_resolution=0s&g0.expr=slo_observation_status%7Benvironment%3D%22gprd%22%7D%20or%20slo_observation_status%7Benv%3D%22gprd%22%7D&g0.tab=0

cc @ansdval