Lazarus didn't became really usable until around 2007 or so and even then it wasn't until ~6-7 years ago when it became stable. Previously you'd get lots of crashes, weird behavior and other issues in your own programs. Your programs would just crash without you knowing why and the debugger integration was abysmal (it still is subpar, but AFAIK that is a GCC issue and is why they are working towards a new custom debugger).

The project might have started in 1999 (actually the codebase is slightly older according to their history page) but it took a decade for it to be usable.

Of course today things are much better. It is the most stable environment i've worked with (as long as you stick with the official stable releases anyway - note that releases from getlazarus.org are not official and often contain immature code) and even though it isn't as fast as Delphi in terms of compilation speed (and sadly the FPC devs do not care about compilation speed... what is with compiler devs these days giving zero care about compilation speed? Sometimes it feels like only Borland cared about it) it still is faster than most environments (except Borland's) i have used.