I can't think of any tools for .net that are really must-haves and that cost money. Maybe resharper but you can survive without it. There are free profilers, decompilers, analysis tools, SCMs, you name it. The only thing you don't get with express is integration with plugins in the IDE. Using .NET with free tools is also easy, connecting to MySQL is just as easy as to MS SQL Server to give an example.
Eclipse has supported Python(with code assist,and class introspection) quite well for a long time before Pycharm. So it's not true.
Anyway most Pythonlsts only use text editors.
How am I biased? I don't work for Microsoft. If using a technology stack makes one biased and thereby (as you imply) invalidates their opinion, then let's just shut down Hacker News right now because nobody is capable of expressing an unbiased opinion in your opinion.
The reality is that Microsoft has free development tools that millions of people use - for free.
It's not convoluted at all.
Want a free on-premises database? Simple. Use SQL Server Express. That will handle a database up to 10 GB.
Want to have Microsoft host your SQL Database for you? Simple. Use Windows Azure SQL Database. $10 per month for 1GB and then $3.96 per GB per month after that up to 10 GB and then cheaper from there.
Have you ever even looked into using Microsoft software or did you just immediately dismiss it without looking at it?