MP definitely had over 1k in it 3-4 years ago, but that's entirely anecdotal because there is no way for me to provide data on that. Current numbers are easiest to discuss because it's a simple matter to get accurate information. I am certain that it was over 1k at that time based on my experience playing at that time but that's all I can give on that.
It is also difficult to use numbers from longer ago because more people played non-steam back then, while as time has gone on a greater percentage of players started using the Steam version. I know that a huge number of MP players were non-steam in 2014/2015/2016, and I can presume that number was even greater before that in 2010-2014, but it's just as likely that a large number of people playing SP were using non-steam. That's why it's totally useless to speculate on numbers from that time period because we will never be able to accurately say anything about it.
I did not make any conclusions about Bannerlord in the posts I've made replying to you. All I did was point out that your claim that Bannerlord's MP is performing similarly to Warband's is completely inaccurate. You are right that there are many reasons why that is the case, but the end result of all of those causes is a terrible MP experience which the overwhelming majority of the Warband MP community, the Warband SP community, the Bannerlord SP community and many of the new players which tried it have totally rejected.
I will reiterate: Warband sits at 10-15% in MP, and these days gets closer to 20% at event time, while Bannerlord manages under 3%.