There is an English expression, "If you can't beat them, join them."
For example,
After competing with Microsoft for so many years, he finally accepted the lucrative offer and joined as their head of software development. You know what they say, "if you can't beat them, join them!"
Is there a 成语 or 俗语 to this effect?
The essence of "If you can't beat them, join them." is "It is better to be practical and join the winning side than being stubborn and stick to one's own position."
The example you gave for this idiom, describes "識時務者為俊傑" (Ones who understand situations and act accordingly, are the elites) very well.
所謂「識時務者為俊傑」，當對手強橫無比，而自己又一無所有時，唯有順應時勢，才不致因彼此對峙而有所耗損。
"Ones who understand situations are elites" means when the opponent is too strong to overcome, you can only conform to the situation to avoid meaningless lost"
无力胜之则从之
21c's entry for join
if you can't beat them join them
[谚语]无力胜之则从之
souhu has an article entitled:
无力胜之则从之，亚马逊说：不服，我要半价称王！
youdao's entry on 胜之 says:
唱片业现在开始意识到，在对付侵权这档子事儿上，他们必须得采取“无力胜之则从之”的思路了。
The music industry is beginning to realize that they must adopt the "If you can’t beat 'em, join 'em" mentality when it comes to dealing with pirates.
another example of usage:
迷上了自拍照,怎么办?我们也许还没有研究出如何治疗这种病方法,但是《国家地理》在最新宣传广告中则采用了一种“无力胜之则从之”策略。
It doesn't seem altogether too common, and most likely is copied over and over from 21c, but if it is showing up in headlines on souhu I would imagine it is quite acceptable.
ed:
a qq article even put:
正如俗话说所:无力胜之则从之。
as the saying goes - if you can't beat them, join them.
I got this:
跟你的朋友走得近，跟你的敌人要走得更近。
Walk close with your friends, walk even closer with your enemies.
