As Morvran says the brackets used to be fixed (1.0-2.0, 2.3-3.3, 3.7-4.7, 5.0-6.3, above that they varied slightly as new stuff got added, 8.0-9.3 was top, once upon a time). However, you could only spawn the lowest BR, unless you had spawn points earned during the game (you could carry forward some earned SP from your last game with that nation… but, surprise, surprise it was bugged AF and you often had 0 carried over). Regardless, you would still need to earn more before you could spawn anything better than base+0.3, but it wasn’t too onerous to rack up enough SP for a top BR aircraft.
Everyone knew what the brackets were; everyone had appropriate line ups; everyone had their ‘starter’ at the lowest BR for each line up. Some starters were very competitive and you might easily stick with it the whole EC. Others at the lowest BR were less useful and rarely got used. There was also a timer on the higher BR aircraft once you lost them - longest on top BR and less as you came down, with base BR having no timer/SP. So, even if you had earned a ton of SP, you couldn’t instantly respawn a top BR aircraft once you lost it. Controversially, this timer also applied to every aircraft of the same type (Fighter, Bomber etc) in your line up at the same BR. While this stopped you from alternating top BR fighters - in those nations which might have that option - it could also lead to bizarre situations where both your 3.0 fighters get locked following loss of one, but you are still allowed to take your 3.3 top ranked fighter (in EC2).
Most people were happy with that, although it could make spading top BR vehicles a little frustrating. However, aside from the top BR bracket, you could always take a top BR aircraft into the next bracket and fly it endlessly, so not that frustrating in most cases unless you were a total lack-wit. There were some who ‘just wanted to fly their favourite aircraft’ and resented needing to fly other things first and then perhaps getting locked out after losing it. Oddly, these ‘favourite aircraft’ were always top BR and they never liked them quite enough to fly them in the next bracket.
Although there was no real player pressure to change the system Gaijin decided to remove the SP requirements and timers, with no other changes. Overnight the top BR aircraft became ‘meta’ and most others became obsolete, irrelevant, useless, unused. Players suggested the rolling BR brackets and Gaijin actually listened, although it took a while before anything happened. While many aircraft are still ‘useless’ on any given day, every aircraft does at least get a chance to be top rated and is top or near top about half the time. Biggest ‘winners’ are around top tier where compression is most severe. You don’t have to spend 20-30 mins earning SP before you can even start earning RP on your top jet, and the lowest of the top BR bracket jets are not always cannon fodder for top BR jets with way better tech.
