As I mentioned, by the end of last year, cars began to converge to a degree. The Ferrari became a threat again in the last several races for instance.
Last year is not directly comparable to this year for the whole host of reasons given, except for the fact that this time of year seems to correlate to a drop in performance from Oscar and possibly that the cars have traits that mean it struggle at several of these latter races. But that is an anecdotal observation.
After that, it's a whole new world. If you're looking for hope or reason, strap yourself in for a bumpy ride.
As to how fast the car was, well, it's different for every driver, and it is subjective.
But the idea there wasn't pressure last year is one that I wouldn't agree with, I think Lando had plenty of pressure last year and got a whole load of grief because of the perception he was bottling it.
Oscar is new to the sharp end though, and for him this is likely a whole new level of pressure. It could be affecting him, or maybe the fact that he has consistently had his poorer results at these races is more than coincidence. On face value Lando has a lot of "tells". Mainly, he tells us
Oscar would be a decent poker player, but you can see his desire to nail this coming through now.
for me. 
"as it seems to be right now" 
)) Happy to be part of this forum and to see some very reasonable and logic posts.